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Full text of "Amphibian"

EYEWITNESS<C^>GUIDES 





Discover the world of frogs, toads, newts, 
and salamanders, their natural history, 
habitats, and fascinating life-cvcli 





ntellas 
bowing colour 
nations 



African 
bullfrog 



Written by 

DR. BARRY CLARKE 

Photographed by 

GEOFF BRIGHTLING and 
FRANK GREENAWAY 




DORLING KINDERSLEY 
London • New York • Stuttgart 




Skeleton of 
r r nam 

: : :- .i 



Poison-dart frog 




Bullfrog 



A DORLING KINDERSLEY BOOK 

Project editor Marion Dent 

Art editor Jill Plank 

Managing editor Helen Parker 

Managing art editor Julia Harris 

Production Louise Barratt 

Picture research Clive Webster 

Extra photography Mike Linley 

This Eyewitness ® Guide has been conceived by 

Dorling Kindersley Limited 

and Editions Gallimard 



First published in Great Britain in 1993 by 

Dorling Kindersley Limited, 

9 Henrietta Street, London WC2E 8PS 

Reprinted 1993 



Copyright © 1993 Dorling Kindersley Limited, 
London 



All rights reserved. No part of this publication 
may be reproduced, stored in a retrieval system, 

or transmitted in any form or by any means, 

electronic, mechanical, photocopying, recording 

or otherwise, without the prior written 

permission of the copyright owner. 



A CIP catalogue record for this book is 
available from the British Library 

ISBN 7513 6004 X 

Colour reproduction by Colourscan, Singapore 
Printed in Singapore by Toppan 





Jeremy Fisher from 
Beatrix Potter's 
(1866-1943) The 
Tale of Mr. 
Jeremy Fisher 

.- JJ> 




Contents 



What is an amphibian? 

8 
Ancient amphibians 

10 
The bare bones 

12 
The importance of water 

14 
Colours and markings 

16 
Self-defence 

18 
Fast food 

20 
Hide and seek 

22 
Senses and survival 

24 
Leaps and bounds 

30 
All fingers and toes 

32 
Mating embraces 

34 
Courtship displays 

36 
Egglaying and parental care 



Frog emblem on 
table service of 
Catherine the 
Great (1729-1796), 
Empress of Russia 



Leaping red- 
eyed treefrog 




38 
Metamorphosis 

40 
Early days 

42 
Frog or toad? 

46 
Tailed amphibians 

50 
Life in the trees 

54 
Earth movers 

56 

Poison-dart frogs and 

mantellas 

58 
Friends and enemies 

60 
Rare and endangered 

62 
Conservation 

64 
Index 




What is an amphibian? 



IN AND OUT OF WATER 
This amphibious car can 
be driven on land or in 
water. The words 
"amphibious" and 
"amphibian" come from 
the Greek amphi and bios 
meaning "double life", 
that is, they can live or 
function on land and in 
water. Most amphibians 
pass from a free-living, 
aquatic (in water), larval 
stage into a terrestrial 
(land-based) adult. 



Living amphibians are divided into three groups - frogs 
and toads, newts, salamanders, and sirens, and the little- 
known, worm-like caecilians. Amphibians are vertebrates 
(animals that have a backbone) like fish, 
reptiles, birds, and mammals. They 

are cold-blooded, which means that their body 

temperature varies with their surroundings. 

Unlike warm-blooded animals (mammals and 

birds) amphibians do not need to eat frequently 

to maintain their body temperature / so their 

food intake increases or decreases with their 

temperature and activity level. Amphibians 

have a naked skin (lacking hair, feathers, or 

surface scales), and can breathe through their 

skin as well as, or instead of, their lungs. 




Skin 

of square- 
marked toad 
(above) 



Skin of tree 
frog (right) 




: 



ONUY SKIN DEEP 

An amphibian's skin is very special. Like all 
amphibians, frogs and toads use it to 
breathe, lose or take up water, produce 
colour patterns and markings for 
defence (pp. 20-21), and to attract 
a mate (pp. 32-33). They also 
secrete mucus from their 
skin to keep it moist and 
prevent damage to the 
skiri's outer layer. 





What is not an amphibian? 



Tegu lizard 
- not an 
amphibian 



This tegu lizard from the tropical parts of South 
America looks similar to a salamander, such as the 
fire salamander (below), and some snakes, particu- 
larly the little worm snakes, look like caecilians, but 
lizards and snakes are reptiles, not amphibians. Reptiles can 
easily be told apart from amphibians by their dry, scaly skin. 

Earthworms and caecilians certainly look very similar, but 
many a biologist has been startled to see the worm they 
had picked up, open its mouth to show an impressive 
Mfc fo set of curved, sharp, little teeth! Also, some tadpoles 

look like small fish, but the lack of 
scales and body fins shows that they 
are quite different. 

Skin of mandarin 
salamander 





ANCESTRAL-: 
Newts and salamanders (pp. 46-49) are more like the ear!; ; 
amphibians than either the more distinctive frogs and toads 
caecilians - the overall body shape has remained basicall 
(pp. 8-9). The head is narrow with smaller eyes and a sir 
than in frogs and toads; the body is longer and more IU r 
and there is always a well-developed tail. The legs ai 
and length, so they walk slowly to moderately fas: 
moving insects and earthworms for thei 




Ancient amphibians 



1 HE FD 51 ami HIBIANS appeared some 360 
mill: ive rs ago during the Devonian 
p eri d . Thev evolved from fishes with 
fleshy, lobed fins that looked like legs, 
and, like Ichthyostega, had fish-like 
features. Like their ancestors, they may 
have been attracted onto land by a good 
supply of food and relatively few enemies 
(pp. 58-59) to prey on them. While their 
ancestors had lungs for breathing air and 
began using their lobed fins for moving 
around on land, the early amphibians 

developed efficient walking limbs. The Great Age of 

amphibians was from the 



hole 

mummi- 
ras tiny. 
- iad entered this 
hollow stone (found in 
England in the 1890s) 
via a small hole at one 
end, but eventually it 
died from a lack of 
food, water, and air. 



Devonian to the Permian 
periods, when they were 
more varied in size and 
shape than they are today. 
Diplocciulus, for example, 
was quite small, while 
Eryops grew to 2 m (6.5 ft) 
or more. Most amphibians 
had become extinct by the 
Triassic period, leaving 
only a few - such as 
Triadobatmchiis and Rana 
pueyoi - to evolve into 
modern amphibians 
(pp. 42-49). 



ifcfe 




Artist's reconstruction of 
Triadobatracluts 




Short 

hind 

leg 





TIME CHART OF THE EARTH 


PERIOD 

(Millions 

OF YEARS 
AGO) 


EARLY 
AMPHIB- 
IANS 


CAECILIANS 


NEWTS, 
SALAMAN- 
DERS, AND 
SIRENS 


FROGS 

AND 

TOADS 


PALEOCENE 
TO PRESENT 
DAY 
(70) 




Only 

caedlian 

fossil 

\ • y 






CRETACEOUS 
(140) 






Earliest 

known 

salamander 


Earliest 
known 


JURASSIC 
(190) 






\ N »/'' 


h-og 


TRIASSIC 
(225) 








• H 


PERMIAN 
(270) 


Eryops 

• 






Trtfldolxi- ] 
trachus ' 


CARBONIFEROUS 

(350) 


• 

Iclilhuo- 

stega 








DEVONIAN 
(400) 


^ 










One-half of 

Tritulobatrnchus 

fossil 



FISHY FINS 
These are reconstructions of 
Ichthyostega, an early 
amphibian from the 
Devonian period in 
Greenland. It had 
some fish-like features, such 
as a tail fin and small scales, 
in its distinctly amphibian 
body, but had fewer skull 
bones and legs suit- 
able for walking. 



Reconstruction - 
of Ichthyostega 




AMPHIBIAN CROCODILE 

This skeleton is of En/ops, a crocodile- 
Like amphibian which lived in swamps 
in Texas in the southern USA during the 
Permian period. These terrestrial creatures 
used their strong limbs to move around on land. 



Wide, flat 

skull, like 

modem 

frogs 




ANCIENT FROG 

This 20-million-year-old fossil frog, Discoglossus, is from 
the Miocene period and was found in Germany. It is 
structurally similar to its close relative from the late 
Jurassic period, Eodiscoglossus', which was found in 
Spain. The modern living species of Discoglossus 
show that they have remained almost unchanged 
over the last 1 50 million years. 




SLIM EVIDENCE 

This fossil sandwich 

(above and left) is the 

only known specimen 

of Trindobatraclms, 

which was found in 

France, dating from 

the Triassic period 

about 210 million 

years ago. It has a 

wide, flat, frog-like 

skull, but contains 

more vertebrae than 

modern frogs do, and 

also has a bony tail 

and short, hind legs. 



Body shape 
of fossil 
salamander 
like that of 
modem 
hellbender 



MORE MODERN FROG 

Well-preserved fossil frog skeletons, like Rami pueyoi 

from the Miocene of Spain, are very like the modern 

European frogs which belong to the same genus, Rami 

(pp. 42-43). Fossil frogs like this help experts to date 

when modern frog groups first appeared . They also 

show how little some groups have changed in the last 

25 million years since the early Miocene period. 





heavy body 



ARROW-HEADED AMPHIBIAN 

This odd-looking amphibian is 

Diplocaulus (60 cm, 24 in long), a 

member of an extinct group which 

lived in Permian ponds in Texas, USA. 



RELATIVE FROM ABROAD 

This fossil salamander, whose Latin name is 
Cryptobranchus scheuehzeri, was found in Switzer- 
land and is about eight million years old. It is a 
close relative of the hellbender, Cryptobranchus 
alleganiensis, the only living member now found 
in the southeastern USA. Fossils like this pro- 
vide evidence that some amphibians, like these 
hellbenders (pp. 48-49), once had a much wider 
distribution and that land masses that are now 
separate were once joined. Unfortt i 
fossil record is poor and theii 
relationship re:- 3i 




The bare bones 



INSIDE OUT 

This 19th-century, half-inside, halt-outside, 
anatomical preparation of an edible frog 
clearly shows the bony framework which 
lies beneath the soft outer tissues. 



Amphibians have simple skeletons with fewer bones than other 
modern vertebrates (animals with backbones) and many fewer 
than their fishy ancestors. This highlights an evolutionary trend 
or overall change in amphibians - towards reducing the number 
of bones in the skull and vertebra (or spine). Caecilians are an 
exception to this rule. Compared with salamanders, they have as 
many, or more, bones in their skull and far more bones in their 
spine. Beginning with a basic, ancestral, salamander-type 
skeleton, evolutionary change within the amphibian 

family has gone in two directions. The frog type 

has a broad head, large eye sockets, 
a short spine (usually no ribs), no 
proper tail vertebrae, and long, 
hind leg bones. The caecilian 
skeleton, on the other hand, has 
a small, almost tubular skull, no 
(or very tiny) eye sockets, a long 
spine with ribs, and no legs at all. 
Comparing skeletons of modern 
amphibians helps to place fossils, 
like Triadobatrachus (pp. 8-9), in 
their correct evolutionary position 
- as an early pre-frog type. 




Presacral, or 
shortened, 

vertebra 



f 






H 






WHAT IS A SIREN? 

Sirens are eel-like amphibians found in the south- 
eastern part of the USA. They are permanent larvae 
which retain external gills throughout their lives and 
have small front legs but no hind legs. Because of 
this unique combination of features, some scientists 
regard sirens (pp. 46-47) as a separate, fourth group 
of amphibians, while others think they are just very 
odd-looking salamanders. Sirens do not have an arch 
around their eye orbits, their teeth are different from 
frogs and salamanders (teeth on the lower jaw are on 
an inner bone), and their jaws have a horny covering. 
The way in which sirens fit in with other amphibians 
is uncertain, but their tail vertebrae look like those of 
the extinct Diplocauhis (pp. 8-9). 






10 




OPEN-PLAN FROGS 

This North American bullfrog skeleton shows some 
of the characteristic features of modern frogs - a 
broad head with large orbits for the eyes; a short 
spine with eight presacral vertebrae (anything 
from five to nine in other frogs); a single 
sacral vertebra (the "hump" in sitting frogs, 
pp. 42-43); the urostyle, a peculiar, rod-like 
bone formed from fused tail vertebrae; and 
long leg, feet, and toe bones, including two 
elongated ankle bones which enable the 
legs to fold for jumping (pp. 24-27). 



Adult skeletons of an 

American bullfrog (left) and 

a common frog (below) 



Cloaca 
Rcctun 




internal 
anatomy of a 
female frog 



"' 





TECHNICOLOUR 1NSIDES 

Frogs do not normally have such colourful insides. 
This old anatomical preparation was dissected, then 
injected with red dye to show up the arteries, which 
carry oxygenated blood, and blue for veins which 
carry oxygen-depleted blood. A frog's heart has three 
chambers - not four as in mammals. There is a pair 
of lungs, and the gut is divided into five distinct 
regions - stomach, duodenum, small intestine, 
colon, and rectum. A single opening - the cloaca 
- is present for getting rid of waste products 
from the gut and urinary bladder and it is also 
part of the reproductive system. The paired 
kidneys are visible, but the ovaries, chest 
muscles, and bones of the pectora.1 girdle 
have been removed from this female frog. 



Sacral vertebra 



SUCCESSFUL BLUEPRINT 

The frog skeleton is the basis of a very 
successful amphibian body plan. With 
relatively few, simple modifications, 
some frogs have become adapted to life 
in trees (pp. 50-53), and even under- 
ground (pp. 54-55). This European 
common frog skeleton may look 
small, but adult frogs of other 
species vary from the size of a 
1-cm (0.4-in) long housefly 
to a fully-grown, 40-cm 
(16-in) long chicken. 





Sacral vertebra (wider 
processes, no ribs) 



;^j 



SALAMANDER- 
STYLE SKELETON 
Of all modern 
amphibians, newts and 
salamanders have changed 
least from the body shapes of their 
ancestors (pp. 8-9). This skeleton of 
a juvenile Japanese giant salamander - 
a mere baby at 0.6 m (2 ft) - shows some 
characteristic features of salamanders. They 
have small- to medium-sized openings for the 
eyes, there are about 16 to 22 presacral vertebrae 
(with a pair of ribs on each, except the first), a sacral, 
and about 18 to 20 vertebrae in the tail. Also, the front 
and hind legs are about the same in size and length. 



- -* 



Rib. 






,**** 



***** 



i*ii& 



ii*U*Xftui 



Compact, narrow skull , 



WORM, SNAKE, OR AMPHIBIAN? 

From the outside, caecilians look rather like worms (pp. 46-47); 
although under the skin they look more like snakes, they are 

true amphibians. The lack of eyes and limbs, the small, compact 

skull, and the increase in the number of rib-bearing vertebrae 

(often 100, or more, as shown here), are the results of extreme 

adaptation to a worm-like, burrowing way of life. 



Skeleton of 
a caecilian 



1 



11 





FLOWER POWER 

ThumbeUna is a children's story 
about a tiny flower fairy stolen by 
a toad, who wanted Thumbelina to 
marry his ugly son. The old toad 
imprisoned Thumbelina on a lily 
pad in the middle of a river, but 
helped by the fishes, she escaped 
and eventually married 
the Prince of the 
Flower People. 



The importance of water 

Water is an essential part of amphibian life. Fresh 
water keeps amphibian skin moist and is necessary for 
reproduction - especially in species that spend all, or 
part, of their lives as larvae under water. In aquatic or 
watery habitats, water passes rapidly through the skin 
and has to be eliminated via the kidneys. In dry areas 
amphibians risk losing more water than they can take 
up. Frogs can reduce water loss by having a less 
porous skin, by seeking out damp, shady places, by 
burrowing, and by taking up water from damp or wet 
surfaces. Some toads obtain almost three-quarters of 
the water they need through a baggy patch or "seat" 
on their pelvis which they press against moist surfaces. Amphibians 
rarely drink water, although a little may be taken in with their food. 
In spite of their vulnerability to sudden water uptake or loss, many 
amphibians have adapted their behaviour and skin surface structure 
to a surprising variety of habitats - to life in ponds and in trees 
(even high in the forest canopy where the only free-standing 
water collects in pockets formed by leaves), and to life in the 
desert, by burrowing and forming cocoons. 



SHIP OF THE DESERT 

Contrary to popular 
opinion, camels do 

not store water in 

their humps (which 

are fat reserves), but 

drink large quantities 

of water to replace 
what they have lost. 




BREATHING 
UNDERWATER 

The larva of the 

tiger salamander 

uses its three 

pairs of large, 

feathery gills 

to breathe 

underwater. 

The deep red 

gills are rich in 

blood vessels, 

which absorb 

the dissolved 

air from the 

water. 




Australian water- 
holding frog 
burrowing 
underground 



-i DESERT FROG 
JL Many amphibians burrow deep 
:nto the ground (pp. 54-55) to avoid 
drying out. In its underground 
;hamber, the Australian water- 
holding frog can survive long 
i :■ 'lights in true desert 
."auditions. 



LIFE 

-\CEEDS ART 
-rags are often 
sed in orna- 
ments and 

-signs, like 
this pretty, 

L-r-holding, 
frog-shaped 
gon, made 
in China during 
. 1 6th century. 





A CAVE SALAMANDER 

The cave-dwelling olm from the cold, underground streams along 

the Adriatic coast (of Italy and Croatia) is a permanent, 
sexually mature larva - like the axolotl. Unlike the • ^ 

axolotl, it will not become an adult if iodine 
is added to the water, or 
if given hormone 
treatment. 




Olms range in length 
from 20-30 cm (8-12 in) 



2 WATER-HOLDING WAYS 
In the underground chamber, the mois- 
ture level is higher and the surrounding 
temperature is lower than outside. The 
frog also stores water in the bladder. 
') 

3 ANOTHER WRINKLE 
The outer lavers of 
the skin are shed to form a 
cocoon, drastically reducing water 
loss. The frog emerges to feed and 
breed onlv when the rains come. 





The adult will live on cin/ land 
in leaf litter or small burrows 



merful 
and 
leg 





California newt 
ranges in length 
from 13-20 cm 
(5-8 in) 



AN UNDERWATER LIFE 
The African clawed toad spends 
most of its life in water, only 
coming onto land to migrate to 
nearby ponds or lakes (pp. 22-23). 
The flattened head and body, powerful 
back legs, and fully webbed feet make 
this toad an excellent swimmer. 



Red, 

feathery 

gills 




CALIFORNIA NEWT 
This newt lays a round clump of 12-24 eggs on under- 
water plants in late winter to early spring. The young 
newts leave the water in autumn or early next spring. 



n g albino 
ig colour) 
nican clawed toad 



Axolotl 





WATER BABY 
In some species of 
newt and salamander, 
larvae never change into adults, 
but remain in the water to become 
sexually mature in the larval state. 
This is known as "neoteny" (pp. 48-49). 
Neoteny may be caused by something in the 
environment - like a low water temperature, or a 
low level of iodine in the water. The axolotl (left) 
is the best known example of a neotenous larva. 




Colours and markings 



THE FROG PRINCE 

The story of the 
princess who kisses a 

frog, magically turning 
him into a handsome 

prince, is a well-known 
fairy tale. In the 1815 

version by the Brothers 
Grimm, the princess 

dislikes the frog, but he 
tricks her into caring 
for him, breaking the 
wicked witch's spell. 



Amphibians have an incredible range of colours and markings, from 
bright blues, reds, and yellows to muddy browns and greens, with a variety 
of stripes and spots. Many amphibians are darker on top, with a completely 
different colour and pattern underneath. Like most animals, amphibians 
either blend in with their surroundings for camouflage (pp. 20-21), or are 
highly coloured to show predators that they are poisonous to eat (pp. 56-57). 
An amphibian's colour may also help absorb or reflect heat, or attract a mate 
(pp. 32-35). The main colour and markings in an 
amphibian's skin are produced by three differ- 
ent colour pigment cells - white, yellow, and 
brown-black - which are found deep in the 
skin. There is no green or blue pigment - a 
frog looks green when the blue part of white 
light is absorbed by yellow cells. Brown-black 
pigment cells can expand to darken, or contract 
to lighten, the animal's skin. An amphibian's 
colour varies with humidity and tempera- 
ture - it may become pale when warm 
and dry, darker if cold and damp. 





THE SAME BUT DIFFERENT . . . 

The intricate patterns on the upper 
surfaces of the head, body, arms, and 
legs of these two primarily green 
horned toads from South America 
give them their common name of 
"ornate" horned toad (pp. 44-45). 
The small individual differences in 
skin colours and markings (left and 
below) are common within a species. 




White's rreefrogs 

from Australia 

k (above) and 

Indonesia 

(left) 




Enormous 

mouth for 

- : 



Pattern breaks 
up toad's shape 





DARKEN DOWN, LIGHTEN UP! 

A change in the background colour of an 
amphibian is a response to changes in the 
strength of light, temperature, moisture, or even 
mood. Light green is the usual colour for these 

White's treefrogs (pp. 50-51), but if they 
move away from a leaf's sunlit surface to 
cool, shady, or damp place they may 
:hange from green to light brown. 



Three ornate 
horned toads 
(left) from 
South America, 
from 9-13 cm 
(3.5-5 in) long 



DIFFERENT COLOUR, 
DIFFERENT SPECIES 

This brown form of horned toad (left) was thought to 
belong to the same species as the two green ones, but it 
was recognized as different in 1980. Although the pattern is 
similar, they are found in different, but nearby, habitats and 
do not interbreed in the wild. They are not polymorphic 
forms because they are not members of the same species. 



14 



Light muddy brown skin 
on back with spots on 
limbs is common frog's 
normal colour unit 
pattern 




A trio of European common frogs 



Polymorphism 



If a species of animal has different morphs, or forms, the species is described 
35 being "polymorphic". The differences between morphs are quite small, 
^uch as colour or size variations. "Polymorphism" does not refer to larger 
differences, or changes, in body shape, nor does it refer to the tadpole and 
adult stages in an amphibian's life (pp. 38-41). Sometimes "polychromatism" 
describes species like poison-dart frogs (pp. 56-57), or African reed frogs, 

iere outstanding variations in colour or pattern are found in a 
>:ngle species. "Dimorphism" occurs where there are 
nly two varieties of colour or pattern. 



COLOUR VARIETY 
These three frogs may 
look different but they are 
all the same species of Euro- 
pean common frog (pp. 42-43). 
The frog on the left is the normal 
colour and pattern, the spotting in the 
middle one is produced by a high density 
of brown-black pigment cells, and the frog on 
the right is more plainly marked. These frogs 
are not polymorphic, but have a very variable 
colour pattern - not distinct colour morphs. 




rightly 

coloured 
parotoid 
gland to 
warn off 
predator 



POLYMORPHIC 

PATTERNS 

Although these European fire salamanders 

(pp. 48-49) all have different patterns, they belong to 

the same species, which is said to be "polymorphic". However, 

because each of these salamanders lives in a separate population 

in different areas of Europe, each belongs to different subspecies. 



15 



Self-defence 



JVIost amphibians are harmless but they have many enemies 
and each year millions are eaten by other animals. While many 
produce poisonous chemicals in their skin, unlike snakes, 
spiders, and scorpions, they lack the means of inflicting a 
poisonous bite or sting. An amphibian's poison-defence 
works only if a predator tries to eat it. The main defence 
is camouflage (pp. 20-21) - remaining hidden and not i 

being seen. If disturbed, many amphibians use a ^k 

startling display behaviour to frighten the enemy 
away or give themselves time to escape. The use of 
poison (pp. 56-57) is usually a last resort in a series ^k 
of defence strategies used to avoid being eaten. >* 




HIDE OR DAZZLE 

The colourful fire-bellied toads 
normally rely on tlieir excellent 
camouflage (pp. 20-21) to stay hidden from 
enemies. If faced by a predator, with no chance 
of escape, the toad goes into a defence posture - 
arching its back and showing the bright, warning 
colours of its 
hands, feet, 
and belly. 




POISON GLANDS 

True toads, like the 

European green 

toad, have an 

enlarged parotoid, 

or poison, gland 

behind each eye. If a 

toad is threatened by 

a predator, a poisonous, 

milky secretion oozes 

from the gland's pores. When 

the gland is pressed, the toad can 

squirt the secretion for a short distance. 

If the predator gets the poison in its eyes or 

mouth, it suffers a burning sensation and muscle 

spasms, causing heartbeat and breathing difficulties. 



, Frogs and toads often inflate 
their lungs with nir if upset 
or disturbed - if threat 
increases they stand 
straight-limbed 



Chilean four-eyed frog 
when threatened 




CALL MY BLUFF 

Many amphibians defend themselves hy bluffing, 
pretending they are different from the way they reallv 
are. This European common toad is standing on its toes, 
its body inflated with air, and its head and body tilted 
forward towards the predatory grass snake. This 
makes the toad appear larger than it really is. With 
the parotoid glands as a back-up defence, this 
behaviour turns the toad from an apparently 
harmless victim into an aggressive, dangerous 
attacker. The snake will probably slither away, 
leaving the toad alone. 




SUDDEN 
SHOCK 

The Chilean 

four-eyed frog has 

a pair of glandular 

eyespot markings on 

its flanks, which are 

normally covered by the 

thighs when the frog is at rest. If the 

frog is threatened, it will suddenly expose the 

eyespots - enough to startle almost any enemy 

The "eyespot surprise" bluff is backed up by a 

foul-tasting poison secreted from the glands. 








PRICKLY CUSTOMER 

The Spanish sharp-ribbed salamander 

has needle-like rib tips, which can 

actually pass through the skin of its body 

wall. This teaches any would-be 

predator a sharp lesson. 



Sharp rib tip 



RAGING 
BULLFROG 

This Budgett's 
frog from 
Argentina may 
look harmless, 
even funny (top), 
but an angry 
Budgett's frog 
(left) can look quite 
frightening. If this 
frog is threatened 
or provoked, it will 
open its mouth, 
scream, make loud, 
grunting noises, and 
may even bite its 
enemy. 




STRANGE 
POSITION 

The Italian 
spectacled 
salamander 
uses two displays 
to avoid its enemies. 
It either plays dead 
or curls its tail for ■ 
to show the bright ~ ; 
underside of its tail (abov% . 
Many other salaman. 
adopt even more unusua 
postures for defend 
usually backed up by ig toul- 

tasting, or poisi-r us, s ret ns 
from glands on the --.: - surface. 



17 




SNACK ATTACK 

Many amphibians 

are the favourite 

food of birds, 

mammals, fish, 

insects, spiders, 

and even other 

amphibians! This 

French earthenware 

plate, c. 1560, shows 

a frog about to be 

eaten by one of its 

main enemies— 

a grass snake. 



Fast food 



Frog launching 
itself towards 
prey , 



LEAP AND SNAP FEEDING 
Frogs are more active feed- 
ers than toads and will not 
often sit and wait for their prey 
- "see it and seize it" is their 
strategy. Launching itself towards a woodlouse, this frog 
has to judge the distance it needs to jump and when to open 
its mouth with split-second accuracy. 



JVLoST AMPHIBIANS WILL EAT ALMOST ANY live food that 

they can manage to swallow or gulp down. Insects, spi- 
ders, snails, slugs, and earthworms form the main part of 
the diet for most adult amphibians. Larger species, like 
the ornate horned toad, will take larger prey, maybe even 
a mouse, while some species are cannibals - a case of frog 
eat frog. There are also specialist feeders - 
some smaller frogs and toads eat only ants or 
termites, and one species of Brazilian treefrog 
eats only berries. Aquatic amphibians, like the 
African clawed toad (pp. 22-23), tend to hang 
just below the water's surface, waiting for tad- 
poles or small fish to swim by. All amphibians 
will gorge themselves if food is plentiful, 
to enable them to survive times 
when food is scarce. 






Woodlouse 



European common 
frog going 
after prey 



2 READY FOR PREY 
As the frog leaps 
it opens its mouth, 
ready to catch the woodlouse with its long, sticky 
tongue. Frogs usually go after fast-moving insects, like 
flies, crickets, and grasshoppers. The frog only gets one 
chance - if it misses it will have wasted its energy. Even 
the slow-moving woodlouse might fall, or get knocked 
off its leaf, and escape, if the frog mistimes its jump. 



Legs and 
body nt 
full stretch . 




A BIG MOUTHFUL... 

The ornate homed toad's huge 
mouth, sit-and-wait feeding method, and camou- 
flaged body markings help it take large, passing 
insects, mice, and other amphibians by surprise. 
When a horned toad opens its mouth, the whole 
of the front end of its body seems to open up! 




SLOW, SLOW, QUICK . . . 

Newts, salamanders, and caecilians tend to eat slow- 
moving, soft-bodied animals, like this earthworm. 
They approach their prey slowly, then make a 
quick, last-minute grab, often turning their 
head on one side. They grip the food using 
teeth in their upper and lower jaws. 



Eyelid starting 
to close 



Woodlouse 



Mandarin salamander 
eating an earthworm 



Tongue flips 
out from 
front of 
mouth 



SUCCESSFUL STRIKE 

With the precision of 

a guided missile, homing in on its 

target, the frog's tongue flips out of the 

open mouth and strikes the woodlouse. 




Making a meal 
of a mealworm 




Watching its prey 



«•■ *< 



rfPSr 



TONGUE FLIPS 

The boy's party 

whistle flips open 

and forward because 

air is blown into it, 

but the tongue of a 

frog or toad flips 

out and over, 

because muscles 

in the floor of the 

mouth push the 

".oneue forward. 



Eyes firmly shut as 
ornate horned 
toad swallows 
Us prey 



I bul 
. tail has 
ppeared 







SEE IT, WATCH 
IT, EAT IT 

Toads are careful, 
deliberate feeders. 
This common 
toad's attention has 
been attracted by a wriggling 
mealworm. It turns its head to- 
wards its prey, watching it intently. 
Some toads may even stalk their prey 
using creeping, cat-like movements. 
Suddenly, leaning over the meal- 
worm, the toad gives a rapid tongue- 
flick, and the mealworm disappears. 
As the toad swallows it blinks and 
the pressure of the eyeball helps 
push the food down. 



. . . TAKES SOME SWALLOWING 

The blinking of the eye 
pushes the eyeball 
down, increases 
the pressure in the 
mouth, and helps 
swallow 




Ready for action 




Tongue flicks out 




■♦.*> 






n 




. . . and mealworm disappears 



^^^ -■*. 









Toad swallows, 
blinking its eyes 




4— Sj£> _> 



19 



4 



HIDING IN TREES 

For many species of 

treefrog (pp. 50-53), just 

being the right shade 

of green is camouflage 

enough. A light stripe on 

its side or yellow spots 

can look like sunlight 

on a leaf. 




Hide and seek 



LEAF MIMIC 

This Asian horned toad provides one 
of the finest examples of the art of 
camouflage in amphibians. The body is 
flattened and its colour is an excellent 
match to the dried leaves and leaf 
litter on the forest floor. Skin flaps, or 
"horns", projecting over its eyes and on 
the tip of its snout look like leaf shapes, 
while the narrow skin ridges and 
glandular folds resemble leaf ribs. 



UNUSUAL 
STRATEGY 

This treefrog from 
Brazil has a very 
unusual form of 
camouflage - it looks 
like a splash of bird 
droppings on a stone. 

BREAKING UP 

Many amphibians 
have a light line 
down their back or 
sides, breaking up the 
easily recognizable 
body shape. In some 
species, like this 
Gray's stream frog, 
the stripe may be 
quite wide. 

PATTERN PERCEPTION 

Finding an African 

square-marked toad 

against any similarly 

coloured background is 

verv difficult. When the 

match is this good (right), 

and the toad remains 

perfectly still, 

it is almost 

impossible 

to see. 



Amphibians are masters of "camouflage" - the art 
of self-concealment. They have exceptional ability to 
use their skin colours and markings (pp. 14-15) to 
hide or blend in against their natural surroundings. 
This helps amphibians avoid being seen, either by 
potential prey or by predators. They can also use 
their skin texture. Some species have skin flaps or 
fringes along the edges of their bodies, which make 
their body outlines look like natural objects in their 
environment, or produce an irregular shape, which 
makes it even more difficult for predators to spot 
their prey. Remaining still or 
adopting a set position 
increases the illusion of the 
amphibian appearing to 
"melt" into the 
background. 










A frican square- *'• 

marked toad on bark 




DISAPPEARING TRICK 

Away from their natural habitat, 
some amphibians appear far too 
highly coloured to ever possibly 
camouflage themselves safely. 
This Oriental fire-bellied toad 
looks like a toy model, painted in 
bright, enamel colours. Yet seen in its 
natural surroundings - a duckweed- 
covered pond, with the brighter colours 
submerged - this gaudy little toad is at least 
as difficult to see as the more subtly coloured 
square-marked toad. 

STONE FROGS 

These Asian painted frogs 

show another aspect of 

camouflage coloration 

and behaviour. A 

burrowing species, 

this frog will dig itself 

into soft earth, moss, 

or leaf litter, with 

which it blends in 

very well. However, 

much of its time may be 

spent underground, emerging 

at the start of the rainy season 

to breed. Its smooth, wet skin 

and mottled colours help it to 

merge into a range of features - 

wet leaves, pebbles, and fallen trees. 




Oriental 
fire-bellied toad 





Spot the 
fire-bellied 

toad in 
duckweed 




Male Asian painted frog 



EASILY SEEN 
Against a plain background, 
this same African square- 
marked toad (left) is easily 
seen. All camouflaged animals 
have to be very careful not to move 
onto a background where they can be 
readily spotted - otherwise the 
advantage is instantly lost. 



African square- 
marked toad 





Female 
Asian painted 
frog is fatter 
and full of eggs 



European 
yellow-bellied 
toad on bark 



CLOSE MATCH 

Some species may closely 
match details of objects in 
their environment or have 
subtleties of shading, marking, 
or colouring on the skin surfaces of 
their backs. The markings on the 
skin of this European yellow- 
bellied toad match the small, 
dark marks commonly 
found on bark, in leaf 
mould, or in soft earth. 
The small patches of 
colour help to disrupt the 
toad's shape and almost 
completely hide its body. 




SHARED STRATEGY 

Camouflage is important 

to the soldier and to Mie 

amphibian for the same 

reason - it enables both 

to live in a hostile world, 

but at the same time it 

provides a certain amount 

of personal protection. 



NO ROAD SENSE 

Every year 

thousands of 

amphibians are 

killed on the 

roads on their 

annual migrations 

to and from their 

breeding ponds. 

Road signs like 

this (right) warn 

motorists about 

migrating frogs 

and toads. 




Senses and survival 

Like other animals, amphibians have five basic senses - 
touch, taste, sight, hearing, and smell. But they can also 
detect ultra-violet and infra-red light, and the Earth's 
magnetic field. Through touch, amphibians can feel 
temperature and pain, and respond to irritants, such as 
acids in the environment. As cold-blooded animals with 
porous skin, amphibians need to respond quickly to 
any external changes. In terrestrial (land-based) 
species, a sudden change in temperature can 
lead to death by drying out, or from freezing 
by rapid chilling. An amphibian's 
senses can also help it obtain food, 
find a mate, and avoid being eaten. 



FEELING THE PRESSURE 

Aquatic frogs have a lateral line 
sense system for detecting pressure 
changes from moving or stationary 
objects in the water. The individual 
lateral line sense organs, called 
plaques, are easily seen on the 
head and along the sides of 
the body on tins African 

clawed toad. 




SIGHT AND SMELL 
Terrestrial species, like the mandarin 
salamander (top left), need good eyesight to spot slow- 
moving prey in poor light, while marbled newts (below 
left) use sight and smell to find food. Like most newts, they 
react more strongly to food in water, showing that smell is 
more useful in an aquatic environment. 



22 



TADPOLES 

TOO 

Lateral line 

systems are also 

found in aquatic 

newts, salamanders, 

sirens, and amphibian 

larvae, like this American 

bullfrog tadpole. Their 

position and development 

vary in different species. 




DELICATE FINGERS 

Surinam toads from eastern and northern parts of 
South America spend their entire life in water. 
They have long, thin, tubular fingers, which 
are used for catching and manipulating prey 
towards the mouth when feeding. The tips 
of the fingers are star-shaped and have 
eight (or 16) smooth, fine ends arranged 
in branched pairs. The fingers themselves 
are covered in tiny spines which help the 
adult to grip slimy prey, like fish. The star- 
shaped tips are only fully developed in adults, 
and are different in related species. 




(1) Vertical pupil of 
red-eyed treefrog 



TEMPERATURE CONTROL 
Amphibians rapidly lose body water by 
evaporation in hot or drying conditions. 
They can sense temperature levels and 

sudden dryness through the skin 

and control their body temperature 

by basking in the sun if too cold, or 

retreating into the shade if too hot. 

This painted reed frog from South 

Africa is reducing the area of its 

body surface exposed to the sun, by 

tucking in its front and back legs. 





(2) Heart-shaped pupil of 
Oriental fire-bellied toad 



PERFECT PUPILS 
Eye colour and pupil shape are very 
variable in frogs: (1) vertical, cat-like for night vision or 
quick response to rapidly changing light conditions; 
(2) heart-shaped; (3) horizontal, the more 
common pupil for normal daylight vision; A 
and (4) round - newts and salamanders also 

have round pupils. &L 




(3) Horizontal pupil 
of Asian tree toad 




Leaps and bounds 

1 hink OF frogs and you imagine them jumping and 
leaping around. But not all frogs can leap - some walk, 
crawl, run, or hop for short distances, and certain tree- 
frogs can even "fly", or glide, from tree to tree (pp. 50-51). 
Almost all treefrogs have sticky, sucker-like discs, or pads, 
on their hands and feet for clinging onto vegetation. The 
way frogs move is partly related to the length of their legs 
- those with short legs walk, crawl, or do short hops, 
while long-legged frogs mostly leap or make extended 
hops. Their behaviour also affects the way they move - 
they may walk slowly, stalking their insect food, or leap 
away in alarm from their enemies. For any frog, the best 
way of escape is to hop it- to make for the nearest cover, 
preferably by a quick leap into water. But once in water, 
adult frogs swim very differently from tadpoles. Their 
active lifestyle and the ability to take fast-moving 
prey have helped make frogs and toads the most 
successful group of modern amphibians, in terms 
of variety and numbers of species (pp: 42-45). 




Leg stretching to 

full length . 



A 



SERIOUS FUN 
These children are 
having great fun 
playing leap-frog, 
but for real frogs 
leaping has a 
serious purpose. 
They leap so they 
can capture their 
food or escape 
from danger. 



. Eye 

closing for 
protection 



Hump still visible 






ONE. TWO, THREE, JUMP! 

"his North American leopard frog is showing how a long, 
graceful leap is made. When a frog is at rest on the ground, 
— ated with its legs folded. Once the frog decides to 
its specially modified heel section just above the 
feel pp. 10-11), and its powerful hind leg muscles are 
action. Immediately before the leap begins, 
frog tenses its leg muscles, and then presses its 
r the ground. The frog's leap has begun. 



- " 






ik 



.,?. 



mm 



* A 



. Leg muscles 
tensing 



-#&< 



* ' 



. ■< 



Right hind 
leg preparing 
to step 
fonoard t 



North American 

leopard frog 

prepares for take-off 



V. 



, Front leg 
cairied down 
and backwards 



•C'fc 



Male green toad 

(6.5 cm, 2.5 in long) 

starts a walk 



RUN, DON'T WALK 
African running frogs (pp. 44-45) live amongst 
hummocks, or mounds, in grassland areas - a 
Mtat where a jumping frog might become tangled 
in the grass stems or leap into the path of a predator. 
S walking or running with the body raised off the 
ground, to clear obstacles, is less dangerous. 



•^* 



- ./O 






African running frog 

(3 cm, 1 ,2 in long) 
in crouching position 
and ready for take-off 



^~-*^ 




Air-borne 
frog shows 
streamlined shape 



Fleshy 
thumb 




LEAPING FOR SAFETY 
African sharp-nosed frogs are experts 
in "leaping-for-safety". This frog, in 
mid-leap, uses its outstretched arms, 
legs, and webbed feet to control its 
flight path and to make sure it lands 
safely. If possible, these frogs will try 
to reach the nearest pond or swamp 
to disappear deep into the water, but 
on the way they may make a series of 
long, consecutive, rapid jumps on dry 
land. Their ability to leap is amazing 
- a related species holds the world's 
distance record for frog-jumping. 
It jumped 10.2 m (33.5 ft) in three 
consecutive jumps, or 5.3 m (17.5 ft) 
in a single jump. 



IN MID FLIGHT 
As the leap progresses, 
the frog's legs unfold and its 
powerful leg muscles propel the 
body forwards in an explosive 
burst of energy. The frog's feet 
remain on the ground for as long 
as possible to give it the greatest 
forward thrust. As the frog takes 
off from the ground, its body 
straightens, forming a streamlined 
shape and the hump in its back, 
seen in a sitting frog, almost 
disappears. The frog's nictitating 
membrane closes up from the 
bottom of the eye for protection. 
The frog is air-borne. 



Left hind leg 
pushing 

backzmnfe 




ON YOUR BIKE 

An alternative 

form of 

locomotion! 



Leftf ont leg 
forward 



Left front and 
hind legs 
together 




Left hind leg 
about to wove 
forward 



O 



~> 



; & 






±% ,,.5- 






m 



1 



■$*•- 

\ Right front leg 
has completed 
its part in the 
sequence ■ 








Green load 
finishes its walk 



SLOW AND STEADY WINS THE RACE 

Some frogs and toads live life at a slower pace, 
but have larger home ranges and must travel over 
greater distances than the more active leapers. Slow- 
moving amphibians can adopt a sit-and-wait plan for 
catching their food (pp. 18-19) - their prey may be slow- 
moving, or concentrated in one area, as with ants and 
termites. Amphibians can defend themselves against 
predators by hiding, and by producing noxious or 
poisonous secretions (pp. 16-17), like the green toad. 
As the toad continues its walking sequence (above), 
its front and hind legs alternately extend forwards, 
then push backwards, propelling the toad ahead. 




?m& 



\ Right hind leg 
outstretched ns 
frog is running 






Right front leg stretches 
forward in next running step 




25 



_ 



Continued from previous page 



, Legs at full stretch 



In and out of the water 



DrVE, DIVE, DIVE 

Down, down, down towards the water's 
surface, the frog holds its arms backwards 
and its legs out straight with the toes 
pointed. Now the frog's body is almost 
streamlined, and as it descends into the 
water, it meets little air resistance. 




Water plays an essential part in a frog's life. Many 
species have to return to the water to mate, lay, and 
fertilize their eggs (pp. 32-33) and to pass through various 
tadpole stages (pp. 38-39) before they change into land-dwelling - 
adults. Because water is denser than air, it takes more effort for a frog to 
move in water than on dry land. Frogs that live in fast-flowing water, where 
there is a danger of being swept away by the current, have developed grasping 
fingers and toes for clinging onto weeds or rocks. Similarly their tadpoles have 
flattened bodies that the water will flow over, and large sucker-like mouths with 
which they can attach themselves to rocks and boulders. Once in the water, a frog 
must overcome the water's surface tension in order to leave it. North American leopard 
frogs use their powerful leg muscles to leap free from the water, while treefrogs climb out 
helped by powerful suction pads on the ends of their fingers and toes (pp. 50-53). 



An Oriental 

fire-bellied toad 

swimming 



Front legs 
extending 
backcvards 



Hind legs kicking out 
and dozen together 



Typical cream-coloured 
ridge along upper jaw 
and also along body 





tf^JZtL 




Drawing 

knees up 



legs 



**0&SF 



SWIMMING FROGS AND TOADS 

When frogs and toads swim, they draw their hind 
upwards towards their bodies; then, in order to propel 
themselves forwards, they shoot them out backwards in a 
straight line. To aid this forward motion they bring their front legs 
down to their sides to form a streamlined shape. People swim in 
this way when they do the breast stroke. In the same way, tadpoles 
swim like newts and aquatic salamanders (pp. 28-29), with their 
newly formed limbs held against the sides of the body. When a 
tadpole develops into a frog, it loses its tail and has to learn to 
swim using its legs. The froglet's body is too short for it to 
continue swimming like a tadpole using "S-shaped" 
movements, so the hind legs must become 
strong enough lo propel it through water. 






rs 



Free floating 
-when at rest 








Front and hind 
legs move together 



Front legs stretched 
forward, as hind 
legs kick out 



^ 











GETTING TO THE TOP 

Treefrogs (pp. 50-53) are well adapted for 

climbing, leaping, and walking on the 

smoothest, shiniest leaf surfaces. This 

little White's treefrog can even climb up a 

near-vertical pane of glass, because on 

the ends of its fingers and toes, there are 

special discs, or pads, 

containing sticky mucus. % ^ 

These pads help a frog 

stick to a surface. Larger, 

heavier treefrogs have extra 

pads beneath the finger and 

toe joints for more sticking 

power, and its belly skin also 

helps it to cling on. 



With the next step, 
right front and hind 
legs come together 




Left 

front and 
hind legs 
closing up 




Tail fin 





Mucus covering 
disc helps frog 
cling to trees 




Lateral line 




MAKING WAVES 
When tadpoles fir?: igglt 
their egg mass (pp. 38-3" 
barely able to swim at all. As Hi 
muscles strengthen and the ta 
develops, the tadpole swims by 
making a series of 5-shaped, or 
undulating, waves which pass 
down the tail from the base to the 
tip. Before the limbs develop (1 ), 
the tail provides all the 
power needed to propel 
the tadpole forward (2). 
As the limbs develop, 
the tail is absorbed. 
The tadpoles have 
changed into froglets 
and are able to swim to 
the edge of the pond to leave. 



American bullfrogs stay in 
the tadpole stage for two to 
three years - these four are 
about two years old, but so 
far only two (3, 4) have 
developed legs 



swim motion 



White's treefrog 
climbing up a 
pane of glass 




Hind leg developing 



, Webbing on foot 
provides some 
of the frog's 
propulsion 
in zeater 



Body curving 
upwards upon 
entering water 




SUPERFROG! 

This leopard frog, 
leaping free of the 
water's surface, 
shows just how 
powerful the leg 
muscles can be. Not 
only do they lift the 
frog's body weight, they 
also have enough extra 
power to overcome the 
water's surface tension. 



North American 
leopard frog 
completing its 
leap into water 



27 



- 



tued from previous page 




On all fours 



Newts and salamanders (pp. 46-49) usually move quite slowly and 
walk or crawl - on land, underground, in the trees, or on the bottom of 
ponds - but they will move quickly to escape danger. Certain species can 
also swim and burrow: the mole and tiger salamanders which burrow with their 
hands and feet, and aquatic newts where the male performs a swimming courtship 
display in front of the female (pp. 34-35). Some salamanders, with stubby, webbed feet 
for gripping leaves, live among grasses, on low bushes, and even high up in the trees. So 
far, no "flying" salamanders have been found, but some "spring" when startled. The legless 
■ - caecilians, however, must burrow - but one group has taken to the water. 



■ 

SWIMMING NEWTS 

Swimming involves many different leg, body, and tail movements. Newts float with 

their legs outstretched and body slightly inflated with air. Slow, lazy, swimming movements 

are made using the legs like oars in a two-person rowing boat. To move raster they paddle 

with the front legs alone or with the hind legs, sometimes alternately, sometimes together. 

Fast swimming and escape movements may also involve rapid flexing of the body and 

lashing the tail from side to side. Watching newts swim tells a great deal about 

what they are doing and how they behave. 



. Tail 
curving 

to left 



Fire-bellied newt 
swimming 



Foot in 
forward 

position 
ready for 
next step 



•<**• un" WW<W ''g'P"l> o< ■« 



k *^'/ 



%£m 










Tail is 
straight 




Foot presses against 

ground pushing 

salamander's 

body forward .^d 


^fo:' ^t 


Tail curves to 
right, helping 
salamander's 
balance, 


j^Hp .* 





Foot 
pushes 
body 
forward . 



European fire 
salamander walking 



Foot in forward position ready 
to press against the ground 
and push the animal 
, forward 



9 




Foot 
moves 



* » : 



This foot 

pushes the 
body forward . 

-i ONWARD AND UPWARD 

JL The European fire salamander walks slowly like most salamanders. 
The legs move in an alternate and opposite pattern, which means that 
the salamander lifts and moves the front foot of one side forward at 
the same time as the hind foot on the other side of its body. The 

other two feet remain in the same position on the ground, 
pushing the body forward, ready for the next step. 



tA 

3 ' r m- 



> 



28 




UNDULATING CAECILIANS 

Most caecilians live in soft earth or in the leaf litter of the 

tropical rainforest floor. About 20 species have moved back 

into the water and swim using undulating, or wave-like, 

movements like the one above. All caecilians can burrow - 

the head is pushed into the soil, opening up the hole with 

movements of the neck. Then they either "swim" forward 

through the soil (using undulating movements passing 

back along the body), or use a special, worm-like concertina 

movement, where the spine (pp. 10-11) folds inside the body. 



With the next step the front right 

rid left hind feet of die salamander 

move together, while the other two feet 

?tay in the same position on the ground 

getting ready to push the body forward 



Foot pressing on 
surface, ready to 
push body forward 



Foot ready to lift 
for next step 



Foot 
pressing 
doum . 



Foot ready to 
lift and move 
body forward 





NEWT WALK 

When on land and moving at slow speed, newts walk in a similar 
way to salamanders. This view from beneath shows which foot 
is actively pressing against the surface, pushing the newt forward, 
and which is being lifted off the surface before being put down 
again. When in water, the newt is lighter and more buoyant (just 

as a person is in a swimming 
pool) and often uses just the 
tips of its fingers and toes 
to walk over the muddy 
bottom of its pond. 




View from below, showing 
how a newt walks 





,Foot 

ready to 

lift and move 

body forward 



Large tubercle 
used for 
digging 




Asian 

painted 

frog 



CLIMBING HAND, 
BURROWING FOOT 

This unusual side view 
of an Asian painted frog 
shows it is well adapted 
to life on the forest floor. 
It has large hands, with 
long fingers and discs on 
the tips for climbing, and 
two enlarged tubercles on 
each foot for burrowing 
(pp. 54-55). 



"Extra" 
bone in 
each finger 
and toe 




All fingers and toes 

An amphibian's legs, hands, and feet can 
give valuable clues to its habits and life- 
styles. A closer look at the front and back 
legs can reveal how an amphibian moves 
- whether by hopping, leaping, walking, run- 
ning, crawling, digging, climbing, or even "flying" 
(pp. 50-51). Hands and feet also show where they 
live: treefrogs have discs on their fingers and toes; 
flying frogs have discs on their fully webbed fingers 
and toes; aquatic frogs and toads, as well as tree- 
living salamanders, have very broad, fully webbed 
feet; and burrowing frogs have short fingers on their 
hands and tubercles (projections of 
thickened skin) on their feet. 




MIXED-UP FROG 

The South American 

paradoxical frog has a 

strange life history. Not 

only does the tadpole 

grow larger than the 

adult frog, but the 

adult's fingers and loes 

each have an extra 
bone, making the feet 
and hands very long. 




White's 
treefrog 



A GOOD CLIMBER 

In most treefrogs 

(pp. 50-53), such 

as this White's 

treefrog from 

Australia, both 

the hands and 

feet are adapted to climbing. 

Their big hands and feet give a 

wide spread, so they can grip 

onto larger areas of leaves, 

twigs, and branches, and the 

sticky pads on their fingers 

and toes help them cling on. 



A GREAT BURROWER 

The short, stubby toes 

and fingers, and. 

t. ^ large, spade-like 

tubercles on the 

African bullfrog's 

feet are adaptations to a 

burrowing life (pp. 54-55). 

Each year it spends up to 

ten months underground. 




HOW UNUSUAL! 
This treefrog from Belize may have 
an unusually shaped head, but it 
has the normal hands and feet of a 
treefrog (pp. 50-53), with long 
fingers and toes ending in sticky 
discs, or pads. The unusual angle 
at the end of each finger and toe, 
above each rounded disc, is 
produced by cartilage (a tough, 
elastic material), which enables 
the last two finger bones to 
slide over one another. Helped 
by the discs, the treefrog can 
prolong its contact with the 
surface of a tree or leaf, even 
if it moves a hand or foot. 




Small 

foot with 
short loes 



Paddle-tail 
newt 





Fully 

webbed foot for 
swimming fastei 




Palmate newt 



FOUR FEET 

These four hind feet give 
some idea of the variety of 
shape found in the feet of 
newts and salamanders. 
Some species - climbers and 
water dwellers that live on slippery 
surfaces, like paddle-tail 
newts - have small, fully 
webbed feet with very short 
toes, sometimes contained 
within the web. Male pal- 
mate newts have fully 
webbed feet (pp. 48-49). 
The mandarin and tiger salaman- 
ders have flattened, digging feet 
with little or no webbing. 




Mandarin 
salamander 



Flattened foot for digging 



■ 





: * 1 






L*>- 




*i 



^■r * 





FROGGY WOULD A-WOOING GO 

Mr. Frog is trying to show what a 

fine frog he is. Male frogs also have 

to prove their fitness to the females 

- by the loudness of their calls. 




SINGING AND FIGHTING 

Many male frogs, like the strawberry 

poison-dart frogs of Central America, 

call and defend their territory - this is 

known as "lekking". The male calls 

from a vantage point (top) and will 

wrestle with any intruders (above). 

TOAD HUG 
Common toads often begin their 
mating embrace, or amplexus, out 
of water, the smaller male being 
carried to the breeding pond by 
the larger female. Egglaying 
and fertilization are delayed 
until they are in the water. 



Mating embraces 

Jtrogs AND TOADS live in an extraordinarily wide 
range of habitats, but whatever the nature of their home 
area - on land, in water, in trees, or underground, they 
have to find a suitable partner and the right condi- 
tions for egglaying (pp. 36-37). Meeting, courting, 
and mating are the three necessary steps before 
egglaying can take place. In most species, the 
males have a distinctive mating call which 
attracts females of the same species, but 
it may also attract predators which are 
always interested in large gatherings 
of their favourite food. Courtship 
behaviours help to identify the part- 
ner as a member of the same species. 
Amplexus - the mating embrace - 
places the male in the right 
position for fertilizing the female's 
eggs. Fertilization usually happens 
as the eggs are laid. Once a suitable 
spawning ground has been found, 
then egglaying can begin. 




FROG FASTENING 

Frogs and toads 
are popular sub- 
jects for all kinds 
of designs, 
like this 
19th-century 
Japanese ivory 
netsuke, used as 
a kimono fastening. 




Male grasping fanak 

under her front legs 




STUCK ON YOU 

This South African rain frog is not yet "glued" onto 
his larger female partner - when he is, his hands will be 
turned palms outwards. The size difference and sticky 
form of amplexus prevents the male being dislodged in 
the underground tunnels where the female lays her eggs. 




Male 

and female 
common toads 
in amplexus — 
on land 



32 




Male and female common frogs 
in amplexus - in water 




A TIGHT HOLD 

This male common frog is grasping his female 
tightly under her arms, pressing his hands against 
her chest - a common form of amplexus, or 
mating embrace. In other species, males may hold 
the female around the waist - in front of the back 
legs - or even around the head. 

Nuptial 
pad 





■ . 










^^^^^<»- 

m------ 










i_ ^w_ 




^ 


BP--'-'> v 


a\ - «r* 


™ '■■%MP.' i 


/ 


"'- H 


- . *ft*afi£B 




^^^^ 


■ .-. 


jW&SSB-HBb 


'■"''&& 


'togjpSr 




i jjt-- i^lSgy 


B*^ 


W^ 




rem* 






1/ A 






1 




THUMB PADS 

Many male frogs and 

toads have nuptial pads - 

patches of roughened skin on 

the thumbs to help hold on to a 

slippery female during mating. 

SLEEPING PARTNER 
A female red-eyed treefrog 
nears a calling male. He climbs 
on her back, holds on, and she 
carries him to a spawning site. 



Courtship displays 



V_OURTSHIP AND MATING, in most newts and salamanders, 
involve a complex behavioural display by the male for 
the female. Not only does a male have to find a mate of 
the same species, but he has to guide the female over a 
small sperm packet, or spermatophore, which he deposits 
on the ground or in a pond. Fertilization is usually internal - the 
female picks up the sperm packet with her cloaca, or reproductive 
organ. In primitive salamanders, like a hellbender (pp. 48-49), first 

the female lays her eggs, over 



MALE PALMATE 
Although he lacks 
the male great crested 
newt's dramatic, high- 
toothed crest, the male palmate 
newt is easily distinguished from 
the female. He has swollen 
cloacal glands, fully webbed 
hind feet, and a tail with a 
pointed tip but 



no fin. 




UNDERWATER BALLET 

The male great crested 
newt is attracted 
by the swollen 
belly of the egg- 
carrying female, as 
well as her lack of crest 
and silvery tail markings. 
She is attracted by the male's 
colourful nuptial, or breeding, 
"dress". 




Male 
Infilling 
tail towards 
female 



DISPLAYING 

The male swims in 

front of the female showing 

his breeding dress. Raising 

the toothed crest on his back, 

and lashing his silvery tail, he 

fans secretions from his 

cloacal glands 

towards the 

female. 





which the male deposits his 
sperm. Caecilians have a 
special kind of internal 
fertilization, where the male 
inserts the end of his cloaca 
into that of the female. 



VAMPIRE SALAMANDER? 

The male mountain dusk)' 
salamander is no vampire, but he 
is scraping the female's skin with 
his teeth to inoculate her with a 
chemical from his chin gland. 
This is to stimulate her 
to accept his court- 
ship advances. 



Silver u 
stripe on 
male's 
tail 





3 NUDGING 
The male deposits his spermatophore, 
then guides the female over it by nudging 
against her side. The 
female uses her cloaca 
to pick up his sper- 
matophore. 




Male 

palmate 

newt 



MUSCULAR MALE 

The male Spanish sharp-ribbed salamander 
has well-developed, muscular forearms, an 
adaptation for a prolonged mating embrace. 
Mating and egglaying can take place over ten 
months of the year, missing out the hottest 
months in Europe of July 
and August. 



FILM VAMPIRES 
Hollywood vampires also use 
their teeth but, unlike the male 
salamander (top), the aim is to 

kill their victims. 



SHOWING OFF 

This 19th-century strongman 
shows off his strength by holding the 
weights with one hand, but could he hold 
on for 24 hours like the male sharp-ribbed salamander? 



34 




Thin tip to tail 



Normal tail - 

fin extends 

to tip 





THE FEMALE OF THE SPECIES 
The female palmate newt lacks the male's fully 
webbed hind feet, swollen cloaca, and thin 
tip to the tail. When she is ready to breed, 
her belly is Rill of eggs. This gives her a 
distinctly tubby appearance, which makes 
the spotting on her sides visible 
from underneath. 





Cloaca 



Female 

palmate 

newt 




DELICATE FEMALE '9 

The female Spanish sharp- 
ribbed salamander's forearms 
are more slender than the male's. 
The male passes beneath the female 
and moves her onto his back. He uses his 
muscular forearms to hold on to her - the\ 
may stay in this position for 24 hours or 
more! He deposits a spermatophore which 

she picks up with her cloaca. Then she 
attaches the eggs to aquatic plants. 



Female Spanish 
sharp-ribbed 
salamander 






STRONG 
SALAMANDER 
The male 

Spanish sharp- \ ' , 
ribbed salamander 
is either very strong 
or must have 
fatigue-free muscles 
to be able to keep 
holding on to the 
female for such 
a long time. 



Pair of 

mating Spanish 

sharp-ribbed salamanders 

(female above, male below) 



Male 
Spanish sharp- 
ribbed salamander 



35 



Egglaying and parental care 

JN ot all amphibians lay large numbers of eggs in water, leaving 
them to hatch into free-living tadpoles, like the European common 
frog. Many amphibians are caring parents and show more ways of 
caring for their eggs and young than fish, reptiles, mammals, or 
birds. The amount of parental care taken seems to be related to the 
number and size of eggs produced - fewer, larger eggs: more care; 
many, small eggs: less care. The kind of care taken ranges from 
choosing a sheltered egglaying site, to enclosing eggs in a protective 
foam, and egg guarding. Some amphibians carry their eggs or tad- 
poles on their back, or in a skin pocket; others take their eggs inside 
the body, into vocal sacs, or even into the stomach. There are also 
two species of toad, some salamanders and caecilians which give 
birth to live young that are tiny versions of their parents. 



STOMACH UPSET 

This fairy tale character 
looks as though she is 
having a bad time. 
So are the most 
remarkable frogs 
of all - the 
Australian gastric 
brooding frogs. First 
discovered in 1972, they 
have not been seen 
since 1981 and may be 
extinct. They were the 
only animals in the 
world known to brood 
their young in the 
female's 
stomach. 





SAFETY DEPOSIT BOX 

The back of this female marsupial, or 
pouched, frog from South America looks 
swollen. The male has placed a hundred or 
more fertilized eggs in the brood pouch on 
her back. After a period of incubation, the 
female makes her way to the water. Using 
the toes on her back feet, she then opens 
up the pouch, releasing the tadpoles into 
the water to complete their development. 





EGG MIMIC 

The pattern on the backs of these two glass frogs 
from the rainforests of Costa Rica, looks very 
similar to the eggs they are guarding. The male's 
camouflage enables them to guard their eggs in 
safety for 24 hours a day. As these frogs are so 
well camouflaged, they can avoid predators and 
feed on any insects that may alight on the leaf. 






A LONG WAIT 

This little lungless 

salamander, found in 

Costa Rica and Panama, is 

a devoted parent, guarding 

her egg clutch for some 

four to five months. The 

guarding parent, which 

may be either the male 

or the female, lies curled 

around the eggs which it 

turns occasionally. This 

protects the eggs from 

both predators and 

fungal infection. 




Male midwife 
toad, ranging from 
3-5 cm (1.25-2 in) 
in length, carries a 
string of eggs 




36 



A SAFE PLACE 

The female Surinam toad looks 
like dead leaves on the muddy 
bottom of the sluggish waters in 
South America where it lives. 
After mating, the male fertilizes 
the eggs released by the female, 
which stick onto a thick, spongy 
layer of skin on her back. 




POCKETS FULL OFTOADLETS 

The eggs are placed on the fe m ale Si 
toad's back, when the male an d 
perform an egglaying roll, ark . ■.- 
movement, underwater. The p 
upside down when the female 
about five eggs which are ferri . 
and drop onto her back as the pair 
turn right way up in the water. In 
all, about 55 eggs are laid in this 
way. After four weeks they hatch 
as perfect, small toad lets. 



Skin of female 
Surinam load swells 
up, almost completely 
covering her eggs 



HITCHING A LIFT 

This little, non-poisonous frog 
from Trinidad is related to the 
more brightly coloured poison- 
dart frogs (pp. 56-57) from 
Central and South America. 
In this species, the male stays 
with its egg clutch. When they 
hatch, he carries the entire 
tadpole brood on his back to 
a nearby stream to complete 
their development. In other 
closely related species, the 
female is the tadpole carrier. 





VOCAL SAC BROODING 

The male Darwin's frog from Chile 
%vatches over his developing clutch of 

eggs and when the newly hatched 
tadpoles start to squirm, he takes them 
into his vocal sac. The tadpoles remain 
there, apparently receiving some form 
of nourishment, until they are ejected 
as tiny froglets. 



THE MALE MIDWIFE 
The male midwife toad from western 
Europe shows a unique form of parental 
care - he carries his eggstring of some 35-50 
eggs, wrapped around his hind legs. After the 
eggs are laid and fertilized, he keeps hold of the 
female and, moving his legs alternately back ar 
forth through the eggs, fastens them securely 
around his legs. After about three weeks, ho tal - 
Ms egg load into the water where the tadpoles 
hatch and complete their development. 



Very short 
tail 




Metamorphosis 



Twisting 
cmbn/o . 



NOW A FROGLET 

At 12 weeks, the tail has 
reduced to a bud and 

will soon disappear. The 

froglets are ready to 

leave the water. Every 

generation re-enacts the 
transition from water 

to land that occurred in 

the first amphibians 

(pp. 8-9). 



JVLetamorphosis is the change from the larval, or 
tadpole, stage into an adult. Amphibians are the 
only four-limbed, or land, vertebrates (animals 
with a backbone) to develop in this way, which 
is easier to see in frogs and toads than in other 
amphibians (pp. 40-41). Frog and toad larvae, 
or tadpoles, look completely different from their 
parents. The most notable difference is that a 
tadpole has an all-in-one head and body, as well as a long tail. 
At first a tadpole lacks legs, which develop later, and it must live 
in water to survive. The time taken to develop from eggs hatching 
to a fully-formed froglet varies from about 12 to 16 weeks, but this 
time span is greatly affected by water temperature and food supply. 
Tadpoles found in colder regions, at high altitudes, or from spawn 
laid in the breeding season, may hibernate in the tadpole state, 
and will not turn into a frog until the following spring. Not 
all frogs and toads have a free-living tadpole. For 
some, development takes place within an egg or 
inside the body of a parent (pp. 36-37). 



Frog's egg 



s- 



&P* 



t> 



- % v 3 *#>■*. ■ 
w -- > ■ .*.* 

2 LIFE BEGINS 
The first signs of life are when the 
central yolk divides in two, then four, 
and then eight - until it looks like a berry 
inside a jelly coating. The developing 
embryo, or tadpole, grows longer and 
twitching, pre-hatching movements 
may be seen. Hatching will take place 
about six days after 
fertilization. 

Female 



9 



♦ • 




# • • I •* 




-i A TIGHT SQUEEZE 
i- The male frog is 
clasping the female 
underneath him, in a 
tight mating embrace, 
called "amplexus". The 
male's arms grasp the 
female behind her front 
legs, as shown here - in 
other species, the grasp 
may be in front of her 
hind legs or around her 
head. Amplexus can last 
for several days. The male 
fertilizes the eggs - the 
numbers can vary from 
a single one up to 20,000, 
or more - as they are laid. 
They may be laid singly, 
in clumps, or in strings 
(pp. 36-37). 



, Tadpole's tail is 
longer than 
its body 



Four newly 
ha tched 
tadpoles 




Tail still 

very long . 



v 




Tadpole 
swims by 

wriggling 
its long tail 



5 FROM SIX TO 
NINE WEEKS 
Between six and nine 
weeks, the hind legs 
appear as short buds. 
At six weeks, the body 
becomes longer and the head 
region becomes more distinct as the 
tadpole grows older. In this tadpole, 
the hind legs are functional and aid the 
tail in propelling the tadpole forward. 
The diet may now include dead insects — 
even dead tadpoles - as well as plants. The 
bulges in the body wall are produced by the 
developing front legs, which 
merge elbow-first through 
openings in the body wall. 



Half-tadpole, half-frog, 
between six and nine weeks 



6 AFTER NINE-WEEKS-OLD 
The tadpole now looks more like a miniature 
frog with a long tail. The scars around the front legs 
show where they emerged through the body wall. 
The tail is gradually absorbed and the froglets 
begin to gather around the edges of the pond. 




\ 



Bulge where 
front leg 
will start 
to prni 



Head starting 
lo take shape s 





3 JUST HATCHED 
On hatching, the tadj .is on 

the remaining yolk in i - ts tail 
mouth, and external gills art p 
developed. The tadpole attac 
to weeds, using two ad hesi re rgans 
behind its mouth but abov£ its 
At seven to ten days, it feeds or 
and begins to swim actively. 



Underside of 
four-week- 
old tadpole 



Hind leg 
helps prope 
tadpole 
forzmrd 




4 AT FOUR WEEKS 
The external gills become 
covered by the body skin - 
then they gradually disappear 
and are replaced by internal 
gills. They feed by using rows 
of tiny teeth to rasp away 
at plants or algae-covered 
surfaces, producing a "soup" 
of vegetable particles which 
are trapped in the mouth. 
The oxygenated, food-laden 
water enters the mouth and, 
after processing, leaves by 
the spiracle. Four-week-old 
tadpoles have a long, coiled 
gut to extract as much 
nourishment as possible 
from their poor diet I 
are active sodal 
and ma -. 
- 



now fully 
formed 



Tadpole between nine 
and twelve weeks of age 



39 



Early days 



Neioly 
laid egg 





Like frogs and toads, newts, salamanders, and 

caecilians undergo a metamorphosis, or period of 

larval development, but the change in 

their body shape is less marked. 

In newts and salamanders, 

the larva looks more like the 

adult. The development of 

the great crested newt is 

typical of species with 

aquatic larvae, but 

many salamanders do 

not have a free-living 

larval stage. Instead the 

female salamander mav 

lay her eggs on land to be 

guarded by either parent, 

or may retain the eggs in 

her body (pp. 36-37). In 

each case, the salamander's 

egg and larval development 

is the same as that of the 

newt, but takes place inside 

either the egg capsule or the 

female's body. In caecilians, 

the species with free-living 

larvae have large gills and, 

like the adults, are limbless. 



EGG SANDWICH 
Newts lay their eggs 
singly. The female 
wraps a waterweed 
leaf around each egg 
immediately after laying 
to hide it from predators, 
and so it has a greater 
chance of hatching. This 
leaf has opened, exposing 
the white egg, which probably 
will be eaten by a passing fish. 



CAREFUL MOTHERS 
This female newt is 
using her feet to wrap water- 
weed carefully around every 
egg she lays. Eggwrapping is a 
simple way of protecting them 
(pp. 36-37) and is much better 
than leaving them exposed in 
open water. Females of some 
other newts (pp. 46-49) - such as 
those of eastern North America 
and the fire-bellied newts of the 
Far East - show this egg-wrapping 
habit. They lay between 200 and 
400 eggs in this way. 




EARLY DAYS FOR A NEWT EMBRYO 

At first, the egg divides like a frog's 

egg - into two, then four, then eight 

cells, and so on, until a berry-like 

cluster of cells is produced. 

After a week or so an embryo, 

with a recognizable head, tail, 

and limb buds, is formed (left). 

Development is rapid and the 

egg hatches after only about 

three weeks. 



Feathery gill 



■■<. Si 




" 



Newt 
larva 






Internal 
fi; organs and gut 

• <v?fp- visible through 
transparent, skin 






One of three 
pairs of 
feathery 
gills . 



NEWLY HAT. 

TO EIGHT WEEKS 

Newt Ian - 

have large eves 

and usually feed 

on water fleas 

and bloodworms. 

They have three pairs 

of feathery gills, unlike 

frog tadpoles which have 

only two (pp. 38-39). Newt 

larvae also develop their 

front legs first, but frog 

tadpoles get their 

,, j hind legs first. 



Typical 

large 

eye 





YOUNG TIGER? 
Tiger salamander larvae are large - 1 .25 err. ).5 in 
long when they hatch and 10 cm (4 in) v, : 
develop into young adults 12 week? later These 
two young tigers show the change:: - 

larva (left) to a nearly-transformed y ung 
tiny gill remnants (above). A young s 
will eat almost any food it can get - 

(pp. 18-19), a habit which > during 

its life. This is why it is ? large -up! - 
(1.5 in) longer than a Pac::: _ - . . - 



41 



Frog or toad? 




Frogs and toads are the most easily recognized amphibians, 
because they have such a distinctive body shape. Separating 
this group into "frogs" and "toads" is not so easy, as the 
features used to distinguish between them do not apply 
in all cases. In general, frogs are more active, are found 
in or near water, have smooth skins, long hind legs, 
and fully webbed feet, while toads tend to be less 
active, prefer to live on land, have dry, warty skins, 
and little or no webbing. Yet some frogs do not live 
near water and have little or no webbing on their 
feet, and some toads have a smooth skin. The 
word "frogs" is often used by 
experts, to include both 
frogs and toads. 




Smooth 
fkin not 
typical 
in toads 




j. Smooth, 
y / wet skin 



LOOKING FOR DIFFERENCES 

The difference between the long (jumping) legs of 
frogs and the short (walking) legs of toads is 
clearly seen above, but some species of frog 
have short legs. Biologists have tried to 
find other ways of telling frogs and 
toads apart and were hopeful when 
they discovered two chest carti- 
lages that were joined together 
in frogs and overlapping in 
toads. But in Darwin's frog 
these cartilages are partly 
joined and partly 
overlapping. 




AFRICAN CLAWED 
?ROG...ORTOAD? 
Some people call this a 
clawed frog, and others a 
iawed toad. It has a very 
smooth skin, lives in water, and 
as fused chest cartilages, so it 
should be called a frog. However, 
Scientific names are less confusing - 
It is known as a Xenopus (zen-o- 
iss) throughout the world. 



Continued from previous page 




EUROPEAN GREEN 

Most treefrogs (pp. 50-53) live 

in South America, but this 

pretty little green treefrog, at 

4-6 cm (1.5-2.5 in) in length, 

is common in most of Europe, 

into Africa and Asia. It lives in 

woods and scrubland, and only 

leaves its tree-top life to mate in 

ponds during the spring. 



Warty, 

toad-like 
skin 



Loads of toads and frogs 

There are more than 3,500 species of frog, 
but new species are still being discovered 
every year (pp. 60-61). Frogs are by far 
the largest and most successful group of 
modern amphibians and are found in all 
the world's continents, except Antarctica. 
Although a few species are adapted to living in cold 
conditions and others live in deserts, the greatest 
variety is found living in tropical rainforests. Frogs 
have a wide range of lifestyles - aquatic, terrestrial, 
and arboreal - that is, .they live in water, on land, 
and in trees, respectively. Some frogs are totally 
aquatic, like the African clawed toad (pp. 22-23), 
while semi-terrestrial species live in and around 
ponds, lakes, fast-flowing rivers, and torrential 
streams. Wholly terrestrial species include 
burrowing frogs, like the mole frog, which cannot 
swim in water. The arboreal, or tree-, frogs are also 
found in bushes, on sedges and grasses, as well as in 
trees. Frogs have evolved a wide range of body 
shapes, sizes, and colours, that enable them to 
survive in widely diverse habitats. 




AUSTRALIAN BURROWER 

Many frogs and toads burrow (pp. 54-55), 

but the aptly named mole frog from Western 

Australia is a supreme example of adapting to 

life underground. A "head-first" burrower 

with a small head and tiny eyes, it uses its 

powerful, muscular front legs, broad hands, 

and stubby fingers to dig, in a mole-like 

fashion. It lives on termites and only comes 

to the surface to mate - when it rains. 



Typical brightly- 
coloured foot 




AFRICAN GIANT 
Adult African bullfrogs can grow 
to 20 cm (8 in) in length. The 
males can be very aggressive 
when defending their 
territories against 
intruders - human or 
even other bullfrogs - 
and are capable of 
inflicting a nasty 
bite (pp. 18-19). 



At 18.5 cm (7.5 in) long the African 
bullfrog is large, but the Goliath 
frog from West Africa is the world's 
biggest frog - up to 
40 cm (15.5 in) 
long 



A HORNED TOAD FROM ASIA 

The fleshy horns projecting over 
the eyes and beyond the snout 
make this a very effective 
leaf-lookalike 
(pp. 20-21). 






Related 
species can 
have much 
smaller, or 
no, horns 




Madagascan 
tomato frogs, 
from 5-7 cm 
(2-2.75 in) long 



f^F 



NO ADDED COLOURS 

These four, fat tomato 
frogs (pp. 60-61) from 
northwestern Madagascar 
really are this deep tomato- 
red colour, and are shaped 
like a tomato as well. 



44 




ASIAN ARBOREALS 

The Asian tree toad, at 
5-10 cm (2-4 in) long, is an 
unusual toad with discs on 
its fingers and toes. Good 
climbers, they live in frees 
and bushes near streams 
in the forests of Thailand, A 
Sumatra, and Borneo 
(pp. 42-43). 




K 



A DEADLY WAITING GAME 

The ornate horned toad from South America 
spends most of its time half buried in forest leaf 
litter or amongst moss, with just the head and eyes 
showing. They are "sit-and-wait" feeders and will 
grab any passing prey - large insects, other frogs, 
and even small mammals (pp. 18-19). 



'.most actual size, 
3 cm (1.2 in) 




HIGH ALTITUDE LIVING 

The Chilean red-spotted toad, found at 

heights of 4000 m (13,000 ft) in 

the Andes Mountains, has 

had to adapt to living at 

high altitudes. 



•-E FROG 

; West African fire 
;'s skin is smooth 
i rubbery, but 
:: secretions will 
K out, if the frog is 
—bed (pp. 16-17). 





UNINVITED GUESTS 
White's treefrogs from 
Australia (pp. 50-51 ) have an even closer 
relationship with humans than the 
Asian painted frogs - they are 
commonly found in outside 
letter boxes, in bath- 
rooms, and even 
in cisterns of 
toilets! 



Only 2.5 cm (1 in) long) 




45 



Tailed amphibians 

Salamanders, newts, and sirens make 
up a group of around 360 species of tailed 
amphibians. Most newts and salamanders 
are found in the cooler, temperate, forested 
areas of the northern hemisphere, but one 
group of lungless salamanders (pp. 48-49) 
extends its range southwards to South 
America to include the high-altitude tropical 
cloud forests of Ecuador. Like frogs and toads, 
tailed amphibians have adopted a wide range 
of lifestyles. Some live on land in damp areas, 
although they may go into the water to breed 
(pp. 34-35). Some lungless salamanders even 
live in trees and have broad, flat, fully webbed 
hands and feet with no obvious fingers and 
toes. Others, like the olm and axolotl, spend 
their whole lives in water (pp. 12-13). The 
caecilians, around 170 species, are found 
only in the tropics and burrow in soft earth 
or mud, often near water, or else swim in 
rivers and streams. 



V6V> 



HERALDIC 

SALAMANDER 
This dragon-like 
salamander - a fabulous 
beast of heraldry and 
mythology - was the 
emblem of the 
French royal family 
in the early 1500s. 
In' this detail from 
the painting, The 
Field of the Cloth of 
Cohi, a salamander 
looks down on the 
meeting between 
England's Henry mm 
and France's Francois I. 



I t 



y&M 



U V ■ 

-/■'■- - 



ON FIRE! 

The sight of bright yellow and 

black salamanders fleeing 

from piles of burning logs 

gave rise to the belief 

|§k\ that they lived in fire, 

hence their name - 

1-21 fire salamanders 




, Short hind leg 
- toes more 
equal in size 
than in frog? 



A 



Tip of crest on great 

crested newt's tail 

only grows on nude 

during mating season 



Tiger 
salamander 



\ Colours and 

patterns of tiger 

salamanders can 

vary greatly 



CAECILIANS 
-THE UNKNOWN AMPHIBIANS 
Few biologists have seen a live caecilian and many 
do not realize that this group of limbless amphibians 
(pp. 6-7) even exists. Caecilians vary greatly in size, 
from 8 cm (3 in) to 1 .5 m (5 ft) in length, and have 
either a very short tail or none at all. Females pro- 
duce live young, or guard small clutches of 30 to 60 
large eggs, which hatch into adult-like, gilled larvae. 



Well-developed tail 



. 



, Silvery 
stripe 

in tail 
of male 



£*Y 



Longer body than 
frogs and loads . 



Skin folds (costal 
grooves) - useful 
when identifying 
salamanders 




I 



k« 



SHY 

^^^ SALAMANDER 

The term "salamander" 

is generally used to refer 

only to terrestrial, or land-based, 

amphibians with tails, although aquatic 

newts and sirens are also members of this 

family. Land-dwelling salamanders are shy 

creatures, living mostly in damp areas under cover 

of fallen trees, logs, and rocks. They vary in size from 

the liny, dwarf Mexican lungless salamander, about 

2.54 cm (I in) long including the tail, up to this 

North American tiger salamander which 

can grow as long as 40 cm (15.5 in). 




WATERY NEWTS 

Newts are semi-aquatic 
salamanders, which 
return to the water in the 
breeding season. They are 
found in North America, 
Europe, western and eastern 
Asia, and Japan. The males, 
particularly those of European 
species like this great crested newt 
(right), develop a courtship "dress" in 
spring and make an elaborate display to 
the female (pp. 34-35). The female lacks 
the crest and silvery tail stripe of the male. 



Continued from previous page 



Newt and salamander assortment 

Newts and salamanders belong to a smaller group of amphibians than frogs 
and toads and number around 360 species. Most live in cool, temperate areas 

of Europe, North America, China, and Japan, but 
one group lives in tropical parts of South America. 
Adapted to a variety of habitats, they climb trees 
and shrubs, burrow, and lead a totally aquatic 
existence (pp. 28-29). The largest group, 
^ about 150 species, have lost their lungs 
entirely and breathe through their skin 
and throat instead. 





"EYE OF NEWT" 
The three witches in 
Shakespeare's Macbeth 
thought this was a 
necessity in their brew. 
"Newt" comes from the 
Anglo-Saxon "efete", 
while "an ewt" became 
"a newt" in Middle 
English. Young newts 
are called efts in 
America. 





SLOW MOVER 

European fire salamanders 

are stocky and heavily built. They prefer damp 

areas near water and hunt slow-moving prey, 

such as earthworms, 




Fire-bellied newts 
are found in China 
and Japan 



NEWTS GALORE 
Most newts live on land, returning to the water 

to breed. In the breeding season, the 
*^w^^. brightly coloured male develops 
a crest along his back and tail. 
Some species also have toe webs, or 
fringes, which are used in courtship 
displays to attract the female (pp. 34-35). 



The great crested newt is 
a protected species in the 
United Kingdom, but 
it is also found in 
other parts of 
Europe 



X 



. .,..•„.,;■•. 



*****# 



Palmate newts live in 

Western Europe and are 

more aquatic than 

common newts 




The crest 
of a male Italian crested iplU||* 
newt is larger and 
more distinctive 
than in a great 
crested newt 




The alpine newt 

(left) is a very 

pretty European 

species, but is 

not confined to 

alpine regions 



The marbled newt 
from France and 
Spain (left) may 

interbreed with 
the great crested 

(above right) to 
produce hybrids 



HEAVYWEIGHT LEAGUE 
The tiger salamander lives 
practically everywhere from 
arid plains to wet meadows all 
over North America. It is the 
largest living land salamander and 
may reach 40 cm (15.5 in) in length. 
They are voracious feeders and will 
even eat other amphibians. Like 
other members of the mole- 
salamander family, they 
live in burrows which 
either belong to other 
animals or which they 
dig for themselves. 

BIG BABY 

This tiger salamander 

larva will change into an 

adult when it is about 12 cm 

(5 in) long - unlike its relative, 

the axolotl, which remains and 

breeds in the larval state 

(pp. 12-13). 




MUDPUPPY 

The North American 
mudpuppy is a 
permanent neotenic 
larval species which 
may take up to six 
years to reach sexual 
maturity. Mud- 
puppies have large, 
deep red gills, four 
toes on each foot, 
and are related to 
the European olm 
(pp. 12-13). 




AT HOME IN THE TREES 
These two young White's 
treefrogs from Australia 
show the alert appearance 
characteristic of treefrog 
species. They have large 
eyes and respond very 
quickly to fast-moving 
insect prey. The fingers 
and toes are very 
well suited for 
gripping and 
straddling 
branches. 



Sticky disc 
on toe used 
for gripping 



Life in the trees 



Finger helps 

treefrog 

grasp onto 

branch 






Leaving the water and moving onto 
dry land allowed the descendants of 
the early amphibians to colonize a 
wide range of new habitats. In 
one particular type of habitat, 
frogs have made a remarkable 
adaptation - they have mastered 
the ability to live in trees. Some 
species spend their entire lives in the 
topmost levels of the tree canopy high 
above the forest floor - they even breed 
up in the trees. Others (the so-called flying 
frogs) have also taken to the air, although 
they glide rather than fly. Not all treefrogs 
live in trees - they also live on bushes, 
reeds, sedges, grasses, and lily pads. Many 
different, distantly related families of frogs 
have adapted independently and on many 
separate occasions to life in these habitats. 
One of the most important adaptations 
the development of sticky pads, or 
discs, on the fingers and toes for 
holding onto smooth leaf 
surfaces. Some treefrogs, like 
the North American cricket 
frogs, have returned to life 
on the ground and have 
lost their adhesive discs. 



Bright green 
colour lis 
camouflage 
in trees , 



NOT ALL 
TREEFROGS 
ARE GREEN 

Treefrogs include 
some of the prettiest of 
all the frogs and can be any 
colour of the rainbow, like the 
painted reed frog (pp. 22-23). 
The yellow reed frog (above) 
from South Africa lives amongst 
lily pads in swampy areas. Poison 
dart frogs (pp. 56-57) also live in 
treefrog-type habitats and have 
finger and toe discs, so they may 
also be thought of as treefrogs. 




RED-EYED 
TREE WALKER 
This red-eyed 
treefrog is a capable 
climber which stalks its 
insect food. It is a "flying" frog 
and can glide between leaves and 
branches in its rainforest home. Red- 
eyed treefrogs are found in Mexico, 
Costa Rica, and Panama. 




EUROPEAN FRIENDS 

This pair of young European green 

treefrogs may grow up to 6 cm 

(2.5 in) long. 

They are easily 

distinguished 

from their 

cousins from 

North America 

(pp. 52-53) by 

their pale cream 

throat and belly. 



V 






Strong, slim hind 

leg for long 

jumping 



FROG DECORATION 

This exquisite frog 
climbing a parasol handle 

was designed by the 

Russian goldsmith, Peter 

Carl Faberge (1846-1920), 

and is part of the 

Royal Collection of 

H.M. Queen Elizabeth II. 



Adhesive disc 



SEE-THROUGH EROGS 

Glass frogs belong to a separate family 

related to the White's, the European, and the 

North American treefrogs (pp. 52-53). From 

above, this glass frog from Costa Rica looks 

as if it were made of frosted glass and is 

transparent when seen from below - 

which is how it got its name. 




STOWAWAY FROG 

This little species of treefrog is found in 
Trinidad, Tobago, the north coast of South 
America, and in the Amazon. Like some of 
the larger, bird-eating spiders, it is 
sometimes accidentally imported 
with bananas into other countries. 




EASY GLIDER 

This beautiful engraving shows a flying 
frog from Southeast Asia in full gliding 
flight - a controlled descent with 
fingers and toes outstretched. A 
flying frog uses the webbing on 
its hands and feet as an air 
brake to glide from tree 
to tree or leaf to leaf. 



"fe" c 










r 






This banana 
treefrog is 3 cm 
( 1 .25 in) long 



\ Belli, of 

banana 

treefrog is 

pale yellow 






Continued from previous page 




GREEN SONGSTER 
Treefrogs are the song- 
birds of the amphibian 
world and their favourite 
calling sites are in trees high 
above the ground. The North 
American green treefrog has 
the tubby body shape, long 
hind legs, and sticky pads 
on the fingers and toes of a 
typical treefrog. Although 
many treefrogs look alike, 
differences in head shapes, 
colours, and markings are 
easily seen by comparing 
this treefrog with White's 
and European treefrogs 
(pp. 50-51). 




A safe haven 



DUCK-BILLED TREEFROG 

Seen from the side, the head of this treefrog 

from Belize has a very unusual shape. The 

snout's bony ridges and "duck-bill" shape 

make the frog's head look very similar to 

that of the duck in this old engraving. They 

also make the frog look less frog-like and 

the bony ridges help to camouflage it 

against tree bark. 



The ancestors of modern tree- 
frogs were probably attracted to 
the safety of vegetation which was 
mostly free from predators and the 
more plentiful supply of insects which 
lived around the plants. Early treefrogs 
were probably better at grasping tall grasses, 
twigs, leaves, and leaf stems than other 
frogs. Many amphibians migrated from life 
on the ground to the surrounding vegetation 
above during the course of their evolution - 
particularly the frogs and toads (pp. 8-9). Many 
modern treefrogs are very vividly coloured. Seen 
away from their natural habitat, it is difficult to 
realize that their bright colours are used 
for camouflage (pp. 20-21), as well as ^m 

for warning - or confusing - . 

their enemies. 



GUESS WHO? 

Kermit is probably 
based on the North 
American green tree- 
frog. Male treefrogs 
sing to attract their 
females -but not 
Kermit. He sings 
his love song to 
Miss Piggy! 



Skin's green colour 
helps treefrog merge 
into background 




Dark markings on 
frog's back match 
tree bark 



BONE HEAD 

The skin on the head of these two 
unusual treefrogs from Belize in 
Central America is fused onto the 
bony, box-like skull - this may help 
to reduce water loss (pp. 12-13). 
The treefrog protects itself from 
predators by backing into a 
hole in a tree trunk, using 
its head to block the 
entrance to its home. 




2 DANGER AHEAD 
Jumping in trees is dangerous. A 
treefrog could easily hit (or miss) a branch, 
injure itself, or become tangled up in leaves 
or stems. Any movement is dangerous 
because it might also attract predators. 



RED ALERT 

This red-eyed treefrog from Central America is 
sitting in a typically alert treefrog posture. Tree- 
nogs peer over the edges of leaves and branches 
:o look out for both prey and predators, while 
hiding as much of them- 
selves as possible 
(pp. 22-23). 




Treefrog's eye 
typically facing 
forward 





3 FULLY STRETCHED 
The bright orange 
colour on the thighs and 
other normally hidden 
surfaces is an example of 
"flash coloration". A sudden 
flash of colour, combined with the 
jumping treefrog's unusual shape, 
confuses its enemies. When treefrogs 
land almost flat onto a leaf surface, 
they make a very quiet "slap" sound. 



Flash colour of bright 
orange (but it can also 
be red, blue, or yellow I 



53 



S\ 2- 




DISAPPEARING ACT 
The Spanish spadefoot toad gets 
its name from the black, horny 
"spades" on its feet, which it uses 
to dig feet first into sand or soft 
earth. It can shuffle its feet alter- 
nately to dig vertical burrows. 




Earth movers 



2 MOVING BACK 
The colour pattern on the frog's back is 
similar to that of the mosses and leaf litter of its 
surroundings. A shuffling movement of the back 
feet takes it backwards, down into the litter. 




Life on the surface is full of danger for amphi- 
bians - of being eaten by predators, of drying 
out (especially in the sun), and of starvation if 
too much energy is spent chasing too little food. 
Camouflage helps reduce the risk of being seen 
by predators, hiding under cover reduces water 
loss, and keeping still helps limit weight loss. 
Most amphibians can dig in leaf litter, or the 
upper layers of the soil, and so solve all three 
problems at once. Some go one step further and 
dig in, leaving just the head showing or disap- 
pearing from sight altogether. They may burrow 
to avoid cold or heat. Amphibian burrows may 
be simple short tunnels under logs or rocks, or 
a vertical shaft filled with loose earth, ending in 
an open chamber. More complex tunnels can be 
over 8 m (25 ft) long, with separate chambers, 
entrances, and exits, to keep out snakes, shrews, 
and rats. Burro wers and non-burrowers alike 
use ready-made burrows, and share their under- 
ground homes with other animals (pp. 58-59). 



3 GOING . . . 
The frog continues to bed itself into 
the litter, helping to cover its shape. It 
may pause at times to see how 
comfortable it is. 



4 GOING... 
The back legs 
have disappeared. 
Now it is the turn of 
the front legs to be 
pushed back and 
forth in the leaf litter, 
making small pieces 
of leaf move over 
the body. 




ODD FROG OUT 

This burrowing frog 

from Mexico is a "feet- 
first" borrower, like the spadefoot toad 
(above), but it is so different from all other frogs 

that it has been placed in a family on its own. 



■V* 






The South African spotted 
shovel-nosed frog 




HEAD FIRST 

The spotted shovel-nosed frog from South 
Africa is a "head first" burrower with a 
difference - it actually uses its head, or 
rather its snout, for burrowing. The body 
is bent forward, head down, with the back 
legs held straight, pushing the frog's snout 
forwards into the soil. Digging is done by 
raising and lowering the snout, scraping 
soil away with its powerful hands. Other 
head first burrowers, like midwife toads 
tpp. 36-37) and mole frogs (pp. 44-45), 
use onlv their hands and feet. 




GONE j, 

Only 
the head is 
showing. 
The frog 
has gained a 
major advan- 
tage by its activity - 
it is well concealed, 
comfortable and 
can reduce its 
water loss, taking 
up water through 
its skin via contact 
With damp soil and 
leaves. By staying still, 
it will not lose weight by 
burning energy chasing after 
food. All it has to do now is 
wait for its prey to walk by. 



5 ABOUT TO CO 
The legs and back half 
of the body are now hidden. 
The wriggling move- 
ments continue; 
the bod v is 
rotated, 
pushing it 
down into 
the leaf litter. 




55 




DANDY FROG 

This exquisitely 
dressed frog, looking 
just like a poison-dart 
frog in his clothes of 
many colours, is all 
puffed up and in his 
Sunday best. 



Bright colour 
helps to warn 
off predators 



Poison-dart frogs and mantellas 

JVIany amphibians are brightly coloured, but the most colourful 

of all are the poison-dart frogs from Central and South America and 

mantellas from Madagascar. These frogs use their bright colours to 

defend their territories from other males during courtship, as 

well as to warn predators that they are poisonous to eat. 

They have had to evolve 

more highly poisonous 

chemicals in their skin as 

their enemies, including 

snakes and spiders, are very 

resistant to milder skin toxins. 






This yellow 

mantella may be a 

colour variety of the green and 

black mantella (below), or a 

different species 





Red flash 

colour helps 

camouflage 

fr°8 



This bright 

mantella has a red 

flash" colour on the 

inside of its leg 



STRANGE NAME 
This species was originally 
given its common name because 
of its typical strawberry-red 
colour, made even brighter by 
deep blue-black flecks. Straw- 
berry poison-dart frogs from 
different areas may have very 
different colours - blue, green, 
vellow, orange, plain, spotted, 
and even black and white. 



Identifying mantellas is very 
difficult - they have so many 
colour varieties (above) 



WAR PAINT 

Some native peoples of North 

America used war paint to strike 

terror into the hearts of their 

enemies. This Hopi Indian chief 

wears orange, red, and yellow - 

the classic warning colours - in 

his headdress. Amphibians also 

use the same colours to frighten 

away their enemies. 



Skin is 
highly toxic 




GOLDEN LOOK-ALIKE 

This golden yellow 
poison-dart frog looks 
very like its close relative 
- the more poisonous 
Phyllohates terribilis 
(pp. 60-61) -but it is 
smaller and has black 
markings on its legs. 





It has recently been 
discovered that the 
golden mantella 
from Madagascar 
produces the same 
kind of chemical 
poisons as South 
American poison- 
dart frogs 




This green 
mantella (first 
described in 1988) 
is from Madagascar, 
where habitat destruction 
is a problem. It is important 
to know about new species 
=o they can be protected 
(pp. 60-61) 




Bright black 
red stripes 
make this frog 
more visible, to 
warn off enemies 





FASCINAT1NC FROGS ^B 

Poison-dart frogs make 

up a fascinating group. Some 

are brightly coloured and highly 

poisonous, having complex chemica 

in their skin. These frogs range in size from 

the very small (at 1.5 cm, or 0.6 in long) to larger 

ones (up to 5 cm, 2 in), like the two highly coloured frogs 

sitting on the leaves (right). Poison-darts are social animals, 

with complex territorial, courtship, and mating behaviours. 



LIFE IN THE PENTHOUSE 

This spotted poison-dart 
frog was discovered in 1984. 
It is found 15-20 m (48-65 ft) 
up hi the treetops of the 

cloud forests of Panama. 

There mav be manv 
more high-level, tree-living 
species of amphibian 
waiting to be discovered. 





POISONED DARTS 
The Choco Indians, 
who live in western 
Colombia in South 
America, poison the 
tips of blow-pipe 
darts, which they 
use for hunting. 
They remove the 
toxin by heating the 
live frog over a 
campfire. Only a 
few species are 
used, but one 
is so poisonous 
(pp. 60-61), that the 
dart has only to be 
wiped against the 
live frog's back for 
it to be deadly. 



HAWAIIAN 
HOLIDAY 

This metallic 



Wlteii colours 

develop, the poison 

develops too 



;reen poison- 
dart frog from 
Costa Rica, 
Panama, and 
Colombia has 
reen introduced 
:nto the islands 
of Hawaii and, 
like some of the 
other species, has 
reen bred in capti 



INSECT SIZE AND SOUND 
This is one of the smallest poison-dart frog 
species (under 2 an, 0.75 in). Discovered 
in 1980 in isolated patches of forest in 
:he Andes Mountains, its scientific name 
means "buzzer" - after its insect-like call. 





Yellow and black 
are warning colours, 
as in this poison-dart 
frog, and in the European 
fire salamander (pp. 14-15) 



TOXIC 
TADPOLES 

Poison-dart frogs 

carry their tadpoles to 

small isolated pools, 

often one at a time, 

where they develop 

their colours and 

skin poisons as 

they grow. 



57 



Friends and enemies 



Amphibians have few friends but many natural 
enemies, and are eaten by a wide range of animals. 
To survive, most amphibians have evolved superb 
camouflage colours and other means of defence 
(pp. 16-17). They also produce large numbers of 
eggs or have a special way of caring for their young. 
People are amphibians' worst enemy and threaten 
their survival with polluting and destroying their 
habitats. But some amphibian friends are animals 
that have dug burrows, unintentionally providing 
them with a home. Sometimes different species of 
amphibian will share a habitat or even burrow to- 
gether. Other friends include people who try to pro- 
tect amphibians and their environment (pp. 62-63). 




THREATENED BY BATf 
In tropical areas, bats have learned to home if 
on calling frogs, but bats do not have things 
all their own way. At least one species of fr 
in Australia (the 
common greer 
treefrog 
known 
eat bats 



FROGS VS. MICE 

Ancient Greeks used 
animals in their fables 
to poke fun at polit- 
ical leaders. In this 
1 6th-century engrav- 
ing of the Trojan Wars, 
the frog-people won 
the war against the 
mice-people, when 
crabs nipped off 
the mice's legs. 






A SECOND SKIN 

Like other amphibians, 
the African dwarf clawed 
toad - a relative of the Surinam 
toad as well as the African clawed 
toad (pp. 22-23) - sheds its skin 
every five to seven davs. This 
action possibly gets rid of 
parasites attached to the 
toad's skin. 



Wrinkled 

skin 
starting to 
lift off and 

shed 




\ 



MANY ENEMIES 

As shown in this print by American artist, John 

James Audubon (1785-1851), many water birds, 

like these black-crowned night herons, 

eat vast numbers of frog. Other 

predators include spiders and 

large insects, as well as 

snakes, mammals, and 

larger frogs. 




DOOM 

In this fable by 

Aesop (620-560 u.i .), a 

mischievous frog tied a 

mouse to his foot. When the 

frog dived into a pool, the 

mouse drowned. A passing 

hawk ate both of them - 

the frog became a 

victim of his 

own prank. 



INDOOR FROG 

Many frog species share 

human homes, especially 

bathrooms, like this treefrog 

from Southeast 

Asia. 



BEST OF FRIENDS 

In western Europe, natterjack 

and midwife toads (left and centre 

in burrow) often share the same 

home. This may be a lifelong 

association between the two. Manv 

other animals, like newts (right in 

burrow), also take advantage of the 

safe retreat of a ready-made 

burrow, with its food 

supply of earthworms, 

spiders, and beetles. The 

burrows may be up to 8 m (26 ft) 

long, with a shallow entrance of 

15-25 cm (6-10 in) below ground. 








-i- 



TOAD AND FRIENDS 

Frogs are popular 

figures on st. 

Here are Mj 

his friends - . 

andBadg 

childrei = : 

5COtfe 

- r - - ; 



Rare and endangered 



JVLany species of amphibian are rarely seen because they are secretive, 
like burrowing frogs, or because their natural habitat is inaccessible. 
Others are seldom found outside a small geographical area. Although 
amphibians new to science are still being discovered at the rate of 15 to 
25 new species a year, many others are becoming rarer due to global 
warming, low water levels, pollution, acid rain, and the destruction of 
their habitats, such as cutting down rainforests or filling in ponds. 
Preserving natural habitats is the most 
important step in preventing 
these fascinating 
animals from 
becoming 
extinct. 



4 , 



-* 






MORE PRECIOUS THAN GOLD 

This 2000-year-old, Chinese gold 

frog is valuable, hut when a species 

disappears, it is gone forever! 




THE WORLD'S 

MOST POISONOUS FROG 

First described as new to science in 1978, this 

bright yellow Phyllobates terribitis deserves 

its name. A poison-dart frog, which 

looks similar to Phyllobates 

bicolor, it is so poisonous 

that it could possibly 

kill a person. 



Tomato colour, 
but typical range 
from deep red to 
pale orange 




NEVER UPSET A SKUNK! 

Skunks have an unpleasant defensive 

behaviour. If provoked, they spray a 

rotten-smelling liquid from glands at 

the base of the tail. The skunk frog 

(below) produces 

its evil smell 

from its skin, 

which exudes 

a thick mucus. 



Skin, when 
touched, 
produces evil 
smell and 
thick mucus 



The poisonous 

Phyllobates tembilis 

was discovered in 

Colombia 





Venezuela 
skunk frog 



A BAD SMELL IN 
THE FOREST 

The Venezuela skunk frog 
was described as new to 
science in 1991. It is the largest 
member of the poison-dart frog 
family (pp- 56-57), but its claim to fame 
resls on the very unpleasant odour which 
it gives off if it is in 
danger. Like its name- 
sake (above), the skunk 
frog uses its odour for defence, 
to drive away its enemies. 



60 



DISAPPEARING NEWT 

The great crested newt is now on the protected 
species list in the UK - a special licence 
is necessary even to examine it 
in the wild. Twenty years 
ago, it was abundant all 
over Europe, but filling 
i in home ponds and 
using agricultural 
poisons have 
taken their toll. 



»*"*> 



WILL THIS SALAMANDER SURVIVE? 
The golden-striped salamander from northern 
Spain and Portugal depends upon natural 
brooks and streams for its larval develop- 
ment. The removal of large amounts 
of water for agricultural and 
human use has seriously 
threatened its survival. 



A STEP IN 

THE RIGHT DIRECTION 

These tomato frogs (left) are endangered, 
like many other frog species in Madagascar, 
but they are listed as an Appendix 1 species, 

which means they receive the highest level of 
protection in law. They have, however, 
been successfully bred in captivity. 

Captive breeding and the protection 
of the natural habitat as nature 
reserves may permit the 
reintroduction of this 
and other frog species 
back into the wild. 





i Great 
crested 
newt's 
tail is 
almost as 
long as 
its body 





AN UNREPEATABLE PHOTOGRAPH? 
Gatherings like this group of male golden toads 
(the females are olive-brown with bright red spots) 
ill the Monteverde Cloud Forest Reserve in Costa 
Rica in 1985 may be a thing of the past. They have 
not been seen at all in this region since 1990. 





ISLAND PROGS 

This is Hamilton's frog, 

the rarest of three native 

species in New Zealand. It has 

been found only on two offshore 

islands in the Cook Strait. One 

population lives amongst a 
pile of rocks known as "Frog 
Bank" on Stephens Island, while 
a second, larger population lives 
in a small patch of forest on 
Maud Island. If rats were 
introduced by 
accident, especially 
onto Stephens Island, this 
rare frog could easily be wiped 
out in a very short time. 



Typical shinning 
golden colour 



UNDER 
THREAT 

This golden 
mantella (pp. 56-57) from 
Madagascar is threatened by habitat 
destruction as are many other species of frog (and 
other animals) on the island. Madagascar has a high 
level of "endemism" - that is, most of its species are 
found only there and nowh-- rU3 



61 




Conservation 



HELPING HAND 

Madagascar tomato frogs are 
endangered. They have been 
bred in captivity successfully, 
so if wild populations become 
extinct, thev will still survive. 



1 he problems people cause by destroying 
habitats such as cutting down rainforests, 
filling in natural ponds, taking water 
from rivers for industrial use, acid rain 
pollution, lowering the levels of fresh 
water, and global warming, all seriously 
threaten amphibian survival. People must change their attitude 
to the environment and its wildlife. Like all animals, amphibians 
have a right to live, undisturbed, in their natural habitat. Creating 
nature reserves, conserving natural habitats, and making places for 
amphibians in gardens and parks, will help ensure their continued 
survival. Studying, making new discoveries, and informing 
people about amphibians all help their conservation and 
show how important frogs, toads, newts, salamanders, 
and caecilians are in the beautiful natural world around us. 



NATURALIST 

Caring young 
naturalists 
help to save 
amphibians, 
by raising 
tadpoles 
from frog- 
spawn and^ 
releasing 
them into 




DOING TOO WELL! 
Introducing foreign species into a country 
can be harmful - they may compete with 
the native amphibians. In 1935, the cane 
toad was introduced into Australia to 
control the cane beetle infecting the 
sugar cane. This toad has bred so 
successfully that it has become a 
serious pest in coastal areas of 
Queensland and northern 
New South Wales. 




POND 
PREDATOR 

Dragonfly larvae 
are found in ponds and streams. 
They are greedy predators and eat frog 
tadpoles and smaller newt larvae using their 
extended jaws. They should not be introduced 
into small ponds which contain amphibian larvae. 



Frog 
tadpole 



Tadpole feeding on n 
small piece of meal - 
it also eats boiled 
lettuce leaves . 



Pond snail keeps 
teater free of too 
much algae 



Newt larva feeds 
on water fleas 




A TANGLE OF TADPOLES 

Raising tadpoles from frogspawn and seeing them 
transform into small adults is fascinating. Sensitive 
to pollution and acid rain in fresh water, tadpoles 
are good indicators of change in the environment. 




Water 
boatman 



Waterweed 
provides oxygen to 
keep pond water fresh 



Neiut larva 
develops front 
legs first, but 
frogs develop 
hind legs first 



62 




RARE TOADS 

The natterjack toad is a 
protected species in the UK. 
Its continued survival depends 
on carefully managing its habitats. 




WATER BOATMAN 

This insect swims upside- 
down in the water, 
using its large, oar- 
like back legs, and 
it also eats tadpoles! 



FEEDING SNAILS 
Watch how snails feed, 
compared with tadpoles 
reared in a tank. They both 
rasp away at algae-covered 
surfaces and aquatic plants. 




GARDEN PONDS 
Garden pond? 
(above) an 
to the - 
amphibians. A garden 
pond can be made quite 
cheaply using . 
polythene, or bu 
liner. The pond should have 
shallow and deep areas and it 
should be as large as possible. 
In the northern hemisphere 
the pond should be at least 
60 cm (2 ft) deep, to prevent 
it freezing solid in winter. 



Vateruxed provides 

■ : ... 



Rubber 

liner - up 
to 60 cm 
(2 ft) deep 




63 



Index 



AB 



lesive discs 26-27, 

50-53 
Aesop 59 

African bullfrog 30, 44, 
African clawed toad 13, 

43-44, 59; feeding 18; 

hands and feet 30; 

lateral line 22 
A frican dwarf clawed 

toad 59 
African reed frog 15 
African running frog 24, 

45 
A frican sharp-nosed frog 

25 
African square-marked 

toad 6, 20-21 
alpine newt 48 
American bullfrog 22-23; 

skeleton 11; tadpole 27 
amphibious car 6 
amplexus 32-33, 38 
Asian bullfrog 54-55 
Asian horned toad 20, 44 
Asian painted frog 21, 30, 

45 
Asian tree toad 23, 42, 44 
Audubon, John James 59 
Australian gastric 

brooding frog 36 
Australian water-holding 

frog 13 
axolotl 13, 41, 46 
Brothers Grimm 14 
Budgett's frog 17 
burrowing 44, 49, 54-55, 

60; sharing 58-59 



camouflage 14-16, 18, 

20-21, 36, 45, 50, 52 

54; colours 56 
cane toad 62 
cannibalism 1? 
Carbonifer. .:- perk i : 
Carroll. Lev. - 1 
Chilean rour-eved frog 17 
Chilean red-spotted toad 

45 
cloaca 13; gland 23; 

mating 34-35 
cocoon 12-13 
cold-blooded animals 6, 

22 
colours 6, 14-15, 44-45, 

49-50, 52-53; breeding 

34, 48; camouflage 

20-21, 58; warning 16, 

56-57 
common newt 48 
courtship, frogs and 

toads 32-33, 56; 

newts 23, 28, 34, 47-48; 

salamanders 35 
courtship display 28, 

32-35, 47-48 
Cretaceous period 8 
cricket frog 50 
crocodile newt 49 
Ciyptobranchus 

alleganiensis 9 
Cryptobrancluis 

sclieudizcri 9 



mmon frog 6, 

,2-4?; amplexus 33, 38; 

development 38-39; 

feeding 18-19; internal 

anatomy 11; markings 

15; skeleton 11; skin 6; 

tadpole 36 
European common toad 

43; amplexus 32; 

defence 17; feeding 19 
European fire-bellied toad 

16 
European fire salamander 

7, 46, 48; colours 57; 

markings 15; skin 7; 

walking 28 
European green toad 16, 

24-25 
eyespot 17 



60-63 

Hamilton's frog 61 
hellbender 9, 34, 49 
hibernation 38, 43 
Ichthynstega 8 
incubation 36 
Italian crested newt 48 
Italian spectacled 

salamander 17 
Jurassic period 8 
larval stage 6, 12, 22, 38, 

40-41, 49, 62; axolotl 

13; caecilian 46 
lateral line 22, 27 
leap-frog 24 
lekking 32 
lungless salamander 36, 

46 



North American leopard 

frog 24-27 
nuptial pad 33 
olm 13, 46, 49 
Oriental fire-bellied toad 

16, 21, 23, 26 
ornate horned toad 14, 

18-19, 45 



spermatophore 34-35 
startle display 16-17 
strawberry poison-dart 

frog 32, 56 
Surinam toad 23, 37, 59 



T 



PR 



M 



FG 



DE 



C 



caecilians 6-8, 34, 46, 62; 

birth 36; burrowing 

28-29; feeding 19; 

metamorphosis 40; 

senses 22; skeleton 

10-11 
California newt 13 



Darwin's frog 37, 43 
defence 16-17,56; 

behaviour 60; 

markings 6, 20-21; 

toxins 15 
Devonian period 8 
diet 6, 18-19, 39, 58 
dimorphism 15 
Diplocaulus 8-10 
Discoglossus 9 
duck-billed treefrog 31, 

52-53 
dwarf Mexican lungless 

salamander 47, 49 
eastern newt 16, 40 
edible frog 10 
eft 48 

egglaying 32, 36-37 
eggwrapping 40 
endemism 61 



Faberge, Peter Carl 51 
fertilization 36; frogs 

and toads 32, 37-38; 

newts 34 
fire-bellied newt 28, 40, 48 
flash coloration 53 
flying frogs 50-51 
foam nest 33 
fossils 8-9 

garden pond, making a 63 
giant salamander, 

Chinese 49; Japanese 

10-11, 49; Pacific 41 
glass frogs 36, 51 
golden mantella 56, 61 
golden-striped 

salamander 61 
golden toad 61 
Goliath frog 44 
Grahame, Kenneth 59 
Gray's stream frog 20 
great crested newt 7, 12, 

48, 61; courtship 34, 47; 

development 40-41; 

skin 7 



Madagascan tomato frog 

23, 44, 60; captive 

breeding 61-62 
mandarin salamander 49; 

eye 22; feeding 19; feet 

31; skin 7 
mantellas 56-57, 61 
marbled newt 22, 48 
markings 14-15,20-21 
marsupial (pouched) frog 

36 
mating 26, 32-35, 37, 57 
metamorphosis 38-41 
Mexican burrowing frog 

54 
midwife toad 36-37, 55, 

59 
migration 13, 22 
mimicry 16, 36 
Miocene period 9 
mole frog 44, 55 
mole salamander 28 
mountain dusky 

salamander 34, 49 
movement 24-29 
mudpuppy 49 
mummified toad 8 



HIJL 



NO 



habitat destruction 57-58, 
60, 62; preservation 



natterjack toad 59, 63 
neoteny 13, 49 
netsuke 32 



paddle-tail newt 31 
painted reed frog 23, 50 
Paleocene period 8 
palmate newt 31, 34—35, 

48 
paradoxical frog 30 
parental care 36-37, 58 
parotoid gland 15-17, 43 
Permian period 8-9 
pheromones 23 
Pliyllobates bicolor 60 
Ph'ytlobates terribilis 56, 60 
poison-dart frog 15, 37, 50, 

56-57, 60; calling 32 
poison glands 16-17, 43 
poisons 16-17, 25, 57; 

agricultural 61 
pollution 58, 60, 62 
polychromatism 15 
polymorphism 6, 15 
Rnna pveyoi 8-9 
Ram temporaria 42 
red eft 16 
red salamander 16 



senses 22-23 
Shakespeare, William 48 
siren 6, 8, 10, 22; lesser 47 
skeleton 8-11 
skin 6-7, 42-43; colour 

14-15, 20-21; glands 15; 

poisons 16, 56-57; 

porous 6, 12, 22; 

shedding 59 
South African rain frog 32 
South African spotted 

shovel-nosed frog 55 
Spanish sharp-ribbed 

salamander 17, 34-35 
Spanish spadefoot toad 54 
spawn (frog) 38 



tadpole 7, 15, 18-22, 24, 

27, 36-37; development 

38-39; poison-dart frog 

57; rearing 62-63; 

swimming 24, 26—27 
teeth 7, 10, 39 
tegu lizard 7 
temperature change, 

effect of 22-23, 54 
Tenniel, Sir John 42 
tiger salamander 28, 

46-47, 49; feet 31; 

larva 12, 41 
toxic secretions 15, 45, 

56-57 
treefrogs 6, 24, 50-53, 59; 

banana 42-43, 51; 

Brazilian 18, 20; 

European 44, 51; North 

American 20, 51-52; 

red-eyed 23, 33, 50, 53; 

White's 14, 27, 30, 45, 

50-52 
Triadobatrachus 8-10 
Triassic period 8-9 
tungara frog 33 



UVWXY 



urostyle 11 

Venezuela skunk frog 60 
vertebrates 6, 10 
vocal sac 33, 37 
warm-blooded animals 6 
warning colours 16, 56-57 
West African fire frog 45 
Xenopus 43 
yellow-bellied toad 16; 

European 21 
yellow reed frog 50 



x\cknowledgements 



Dorling Kindersley would like to 

thank: 

Peter Hayman of the British Museum, 
Harry Taylor of the Natural History 
Museum, and Michael Dent (London) 
for additional special photography. 
Dr. Gerald Legg, Jeremy Adams, and 
John Cooper of the Booth Museum 
(Brighton); the British Dendrobates 
Group; Peter Foulsham of the British 
Herpetological Supply; Ken Haines; 
David Bird, Myles Harris, Fiona 
MacLean, and Robert Stephens of 
Poole Aquarium; Regent Reptiles; 
the Reptile-arium; and Roger Wilson 
of the Rio Bravo Field Studies Centre 
(Belize), for providing species 
information and specimens for 
photography. The staff of the British 
Museum (especially Lesley Fiton, 



Catharine Harvey, Sarah Jones, 
Richard Parkinson, Peter Ray, and 
James Robinson), and the Natural 
History Museum (especially Ann 
Datta, Dr. Angela Milner, and Tim 
Parmenter) for their research help. 
Doris Dent and Alan Plank for 
providing props for photography. 
Alex and Nicola Baskerville, and 
Amy Clarke as photographic 
models. Celine Carez for research 
help. Manisha Patel, Sharon 
Spencer, and Helena Spiteri 
for their design and editorial 
design assistance. 
Jane Parker for the index. 

Illustrations Joanna Cameron 



Picture credits 

t=top, b=bottom, c=centre, l=left, r=right 

ZdenekBerger: 8tc. 

Biof otos: Heather Angel 23tr, 35br. 

Prof. Edmund D. Brodie Jr.: lobcr, 17bcr, 

47cr,49c,49bl,56c. 

Dr. Barry Clarke: 20ber, 23tc, 50cl, 62 tr. 

Bruce Coleman Ltd: John Anthony 61tr; 

Jane Burton 1 6tr; Jack Dermid 16tcr, 49cb; 

Michael Fogden 61cr; Jeff Foott 60 cr; 

A.J. Stevens 55tl,55cl. 

Dorling Kindersley: Frank Greenaway 380, 

38tr, 38b, 39tr, 39cr; Colin Keates 8b, 9tc, 9tr, 

Dave King 1 1 tl; Karl Shone 7tr; Kim Taylor 

and Jane Burton 39d, 39b; Jerry Young 12tr, 

20bl,23tr,30cl,44cr,50b. 

Mary Evans: 14tl, 32tl, 46cL 48tr, 56tL57cr. 

Copyright Jim Henson Productions, Inc. 

Kermit the Frog is a trademark of Jim 

Henson Productions, Inc. All lights 

reserved: 52tr. 



Image Bank: Al Satterwhite 21br. 

Kobal Collection: 34bc. 

Mike Linley : 1 3tr, 17bl, 1 7cl, 20tcr, 32tcr, 

32bcr,32bl,32bc,54t 

Musee Nationale d'Histoire Naturelle: 

8tr, 9tl. 

C.W. Myers, American Museum of Natural 

History: 57tcl, 57cl, 57bL 60bi, 60bc. 

Motoring Picture Library, National Motor 

Museum at Beaulieu: 6tl. 

Naturhistoriska Riksmuseet: 8c. 

NHPA: ANT 44tr, 61bl; Stephen Dalton 25tl, 

27bl; Jany Sauvanet: 29cr, 46cb. 

Oxford Scientific Films: Kathie Atkinson 

13tl, 13tc; Jim Frazier 13r; Michael Fogden 

22tcr, 51tc, 51c; Z. Leszczynski7cl. 

Royal Collection, St James's Palace, 

copyright Her Majesty the Queen: 46tr, 51 tl. 

Paul Verrell: 43c 

Zefa: 56cr; K & H. Bensor 19bcL 







Here is an ori g inal and excitin g new guide to the 
extraordinary natural history, behaviour, and 

evolution of amphibians. 

Stunnin g real-life photo gra phs of fro g s and toads, 

newts and salamanders, and rare caecilians, offer a 

unique "eyewitness" view of the double lives of 

amphibians on land and in water. 

SEE 

a toad with heart-shaped eyes • the skeleton of a 

giant salamander • a midwife toad carrying its eggs 

on its back • a female newt wrapping her eggs 

in a leaf • a "duck-billed" treefrog 

LEARN 

the difference between frogs and toads • how 

treefrogs can walk upside down • what an axolot! 

looks like • what makes a toad puff up 

DISCOVER 

why some frogs swallow their own eggs • how a 
lungless salamander can breathe • why a frog sheds 
its skin • how a newt tadpole develops into an adult 

and much, much more 



A DORLING KINDERSLE Y BOOK 



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V t 



i 






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